diff --git a/paddlespeech/s2t/decoders/README.md b/paddlespeech/s2t/decoders/README.md
index ee7d53deaec42e48ad62fe7e594e01df9586f184..0b91ddd1b1b9a61dbb7421c89ca853cb62a1444f 100644
--- a/paddlespeech/s2t/decoders/README.md
+++ b/paddlespeech/s2t/decoders/README.md
@@ -1,4 +1,5 @@
 # Decoders
+we borrow a lot of code from Espnet Apache 2.0  (http://www.apache.org/licenses/LICENSE-2.0)
 
 ## Reference
 ### CTC Prefix Beam Search
diff --git a/paddlespeech/s2t/decoders/beam_search/batch_beam_search.py b/paddlespeech/s2t/decoders/beam_search/batch_beam_search.py
index 3fc1c435f28ba81bfe25e9311f3706caa8c9bcae..ed9790cdff7ba8f4566d90995ea0e8992fccb11e 100644
--- a/paddlespeech/s2t/decoders/beam_search/batch_beam_search.py
+++ b/paddlespeech/s2t/decoders/beam_search/batch_beam_search.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 
 
 class BatchBeamSearch():
diff --git a/paddlespeech/s2t/decoders/beam_search/beam_search.py b/paddlespeech/s2t/decoders/beam_search/beam_search.py
index 6c4f069d855dfb8ad4bbc7025867be278d3ff4fb..7d79246df9b8249258ec09aa8c51f812c401995c 100644
--- a/paddlespeech/s2t/decoders/beam_search/beam_search.py
+++ b/paddlespeech/s2t/decoders/beam_search/beam_search.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Beam search module."""
 from itertools import chain
 from typing import Any
diff --git a/paddlespeech/s2t/decoders/recog.py b/paddlespeech/s2t/decoders/recog.py
index d0710f9c40d1ad547484a86c9b0ba54ee38abbb0..d9324ca02ad5fff81f8c386282dfbce9683b0d5c 100644
--- a/paddlespeech/s2t/decoders/recog.py
+++ b/paddlespeech/s2t/decoders/recog.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """V2 backend for `asr_recog.py` using py:class:`decoders.beam_search.BeamSearch`."""
 import jsonlines
 import paddle
diff --git a/paddlespeech/s2t/decoders/recog_bin.py b/paddlespeech/s2t/decoders/recog_bin.py
index e4d81f40916306933ee5ae7e060cc7bfa61f72d9..cd7a360ae253cdcdf59e641f9adefc4ca87dc299 100644
--- a/paddlespeech/s2t/decoders/recog_bin.py
+++ b/paddlespeech/s2t/decoders/recog_bin.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """End-to-end speech recognition model decoding script."""
 import logging
 import os
diff --git a/paddlespeech/s2t/decoders/scorers/ctc.py b/paddlespeech/s2t/decoders/scorers/ctc.py
index 74a5f578dd8d7feb8229a850b458c6b13e12f263..e0ff3d5f963375457b65a0f3a2b34a039b24b657 100644
--- a/paddlespeech/s2t/decoders/scorers/ctc.py
+++ b/paddlespeech/s2t/decoders/scorers/ctc.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """ScorerInterface implementation for CTC."""
 import numpy as np
 import paddle
diff --git a/paddlespeech/s2t/decoders/scorers/length_bonus.py b/paddlespeech/s2t/decoders/scorers/length_bonus.py
index 864e22d1794ee4e1a9bffe68107acbe8c0378f7d..2e4c84651969d910c9d2ed3dc56c3cfbe6487a8d 100644
--- a/paddlespeech/s2t/decoders/scorers/length_bonus.py
+++ b/paddlespeech/s2t/decoders/scorers/length_bonus.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Length bonus module."""
 from typing import Any
 from typing import List
diff --git a/paddlespeech/s2t/decoders/scorers/ngram.py b/paddlespeech/s2t/decoders/scorers/ngram.py
index a34d82483f95051305a2e692dfd48afe7373dafb..fa8f776af2144aeedb9d6ca20dc7ba62bcbbcfb7 100644
--- a/paddlespeech/s2t/decoders/scorers/ngram.py
+++ b/paddlespeech/s2t/decoders/scorers/ngram.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Ngram lm implement."""
 from abc import ABC
 
diff --git a/paddlespeech/s2t/decoders/scorers/scorer_interface.py b/paddlespeech/s2t/decoders/scorers/scorer_interface.py
index 366904a4703ab5323416b8ff8150a181a5809db6..ddc780da246ffa7a2438a2adf1e041f207ebab2c 100644
--- a/paddlespeech/s2t/decoders/scorers/scorer_interface.py
+++ b/paddlespeech/s2t/decoders/scorers/scorer_interface.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Scorer interface module."""
 import warnings
 from typing import Any
diff --git a/paddlespeech/s2t/decoders/utils.py b/paddlespeech/s2t/decoders/utils.py
index 7dff14c11199d7de05f5c246d9d845aafaf13c68..63709d1a94ba6aec29c3aa9ed8fffe7d05e8b19d 100644
--- a/paddlespeech/s2t/decoders/utils.py
+++ b/paddlespeech/s2t/decoders/utils.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import numpy as np
 
 from paddlespeech.s2t.utils.log import Log
diff --git a/paddlespeech/s2t/io/batchfy.py b/paddlespeech/s2t/io/batchfy.py
index 3517f059af3d52b6bb3fc285864be9f15fc0a194..9be37c2770a12fb7b66ab2e6152d78258fc2100c 100644
--- a/paddlespeech/s2t/io/batchfy.py
+++ b/paddlespeech/s2t/io/batchfy.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import itertools
 
 import numpy as np
diff --git a/paddlespeech/s2t/io/converter.py b/paddlespeech/s2t/io/converter.py
index 94634360c41100f9f518c065570b4a93d4e3f9ce..aacbad9806dc7df98bd1a64ea6bfb051c935790e 100644
--- a/paddlespeech/s2t/io/converter.py
+++ b/paddlespeech/s2t/io/converter.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import numpy as np
 
 from paddlespeech.s2t.io.utility import pad_list
diff --git a/paddlespeech/s2t/io/dataset.py b/paddlespeech/s2t/io/dataset.py
index 121410c8b383f381e255fa9f718204fb68059d5f..4aff9fb2e8cfec691fb6c15e4aeede402e1c3a38 100644
--- a/paddlespeech/s2t/io/dataset.py
+++ b/paddlespeech/s2t/io/dataset.py
@@ -11,6 +11,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 from typing import Optional
 
 from paddle.io import Dataset
diff --git a/paddlespeech/s2t/io/reader.py b/paddlespeech/s2t/io/reader.py
index faf2f600bcb3e8d7ae3ccc12b8f7c2146654b9b4..1e32e620cbc6397ee5f1331ff2a9c50ce9facff9 100644
--- a/paddlespeech/s2t/io/reader.py
+++ b/paddlespeech/s2t/io/reader.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 from collections import OrderedDict
 
 import kaldiio
diff --git a/paddlespeech/s2t/models/asr_interface.py b/paddlespeech/s2t/models/asr_interface.py
index ece83e516b15470d31122cfc3eadf8d9346c5f66..76ba3e2cf05698930e3435849e029cc49256fb2e 100644
--- a/paddlespeech/s2t/models/asr_interface.py
+++ b/paddlespeech/s2t/models/asr_interface.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """ASR Interface module."""
 import argparse
 
diff --git a/paddlespeech/s2t/models/lm/transformer.py b/paddlespeech/s2t/models/lm/transformer.py
index 447f1dbc3bb5a4b86731ec6be52bac5b3af4ab26..3fadba1a39860602892aaed639e6c7a4aa575b75 100644
--- a/paddlespeech/s2t/models/lm/transformer.py
+++ b/paddlespeech/s2t/models/lm/transformer.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 from typing import Any
 from typing import List
 from typing import Tuple
diff --git a/paddlespeech/s2t/models/lm_interface.py b/paddlespeech/s2t/models/lm_interface.py
index 7ae39b351465c06cd4bfafea4f72ab6106b919b9..02df874f15118bee522679c4dcb42ffe75f6f968 100644
--- a/paddlespeech/s2t/models/lm_interface.py
+++ b/paddlespeech/s2t/models/lm_interface.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Language model interface."""
 import argparse
 
diff --git a/paddlespeech/s2t/models/st_interface.py b/paddlespeech/s2t/models/st_interface.py
index 331f1e824d44c65fbff8b5a1c54a34c5f7111a80..66ba49da5d4eb190da57da42d7da0d3e0275f205 100644
--- a/paddlespeech/s2t/models/st_interface.py
+++ b/paddlespeech/s2t/models/st_interface.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """ST Interface module."""
 from .asr_interface import ASRInterface
 from paddlespeech.s2t.utils.dynamic_import import dynamic_import
diff --git a/paddlespeech/s2t/modules/attention.py b/paddlespeech/s2t/modules/attention.py
index d5246777c57386b280e7e613baf853d9e7a9ba50..5cb37ee7fca6e7837bbdc4f00fb5698f7327d3c9 100644
--- a/paddlespeech/s2t/modules/attention.py
+++ b/paddlespeech/s2t/modules/attention.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Multi-Head Attention layer definition."""
 import math
 from typing import Optional
diff --git a/paddlespeech/s2t/modules/cmvn.py b/paddlespeech/s2t/modules/cmvn.py
index 9aa938af7d0e20f05f7afc3eda748e7853dd36b7..df529c1c49a23992a368f85bafdb81e212ce9081 100644
--- a/paddlespeech/s2t/modules/cmvn.py
+++ b/paddlespeech/s2t/modules/cmvn.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import paddle
 from paddle import nn
 
diff --git a/paddlespeech/s2t/modules/conformer_convolution.py b/paddlespeech/s2t/modules/conformer_convolution.py
index 39b1ee3275bd2c7aa85012976cd9e4d9d75a09da..b4632d42928f02d7de5c5e892835037ba522c1aa 100644
--- a/paddlespeech/s2t/modules/conformer_convolution.py
+++ b/paddlespeech/s2t/modules/conformer_convolution.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """ConvolutionModule definition."""
 from typing import Optional
 from typing import Tuple
diff --git a/paddlespeech/s2t/modules/decoder.py b/paddlespeech/s2t/modules/decoder.py
index 7d545f5e87718550b3a29884f284f21896feca11..bd3760c483c81beacc4372a82efcdb740d5d3f2c 100644
--- a/paddlespeech/s2t/modules/decoder.py
+++ b/paddlespeech/s2t/modules/decoder.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Decoder definition."""
 from typing import Any
 from typing import List
diff --git a/paddlespeech/s2t/modules/decoder_layer.py b/paddlespeech/s2t/modules/decoder_layer.py
index 816bc9f619d1e6c3fe3d8f680c5be75bb778cdfe..62682bfbef40135ce82d798e0d2acadae2a6e4e7 100644
--- a/paddlespeech/s2t/modules/decoder_layer.py
+++ b/paddlespeech/s2t/modules/decoder_layer.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Decoder self-attention layer definition."""
 from typing import Optional
 from typing import Tuple
diff --git a/paddlespeech/s2t/modules/embedding.py b/paddlespeech/s2t/modules/embedding.py
index 938898c13ac236e5334ac36f2e46cf9c930756cc..2b92aafe64fe017070da04a3f71a9a2cc8d7ccf2 100644
--- a/paddlespeech/s2t/modules/embedding.py
+++ b/paddlespeech/s2t/modules/embedding.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Positonal Encoding Module."""
 import math
 from typing import Tuple
diff --git a/paddlespeech/s2t/modules/encoder.py b/paddlespeech/s2t/modules/encoder.py
index 246536dbe70045ec4c2552c09a0636aae58e04af..bf9cfeaa67690794313399dfeca7e471f3cb0111 100644
--- a/paddlespeech/s2t/modules/encoder.py
+++ b/paddlespeech/s2t/modules/encoder.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Encoder definition."""
 from typing import List
 from typing import Optional
diff --git a/paddlespeech/s2t/modules/encoder_layer.py b/paddlespeech/s2t/modules/encoder_layer.py
index 0525a6147a436770cccaf34fe187abf4dc110dce..7cff5442f0a5c642fb1380e205d6fb34ecd6e8e9 100644
--- a/paddlespeech/s2t/modules/encoder_layer.py
+++ b/paddlespeech/s2t/modules/encoder_layer.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Encoder self-attention layer definition."""
 from typing import Optional
 from typing import Tuple
diff --git a/paddlespeech/s2t/modules/loss.py b/paddlespeech/s2t/modules/loss.py
index 012ef242608093f6a6a8b62bb55613c62f30f0b2..90f941f7ae3a9ccf2f5ab7a5c31c6b20125534eb 100644
--- a/paddlespeech/s2t/modules/loss.py
+++ b/paddlespeech/s2t/modules/loss.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import inspect
 
 import paddle
diff --git a/paddlespeech/s2t/modules/mask.py b/paddlespeech/s2t/modules/mask.py
index 5c7886d459d23ad434a560478e9c6a2ae831e31b..964d5086f05f296d2d02c6d154c2b585ae912d1b 100644
--- a/paddlespeech/s2t/modules/mask.py
+++ b/paddlespeech/s2t/modules/mask.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import paddle
 
 from paddlespeech.s2t.utils.log import Log
diff --git a/paddlespeech/s2t/modules/positionwise_feed_forward.py b/paddlespeech/s2t/modules/positionwise_feed_forward.py
index ccea8e57d8d4880996f5ad1d1fd70fe14660435f..0d9c2e296c885d3c9911df5513cb8ad0bc299df2 100644
--- a/paddlespeech/s2t/modules/positionwise_feed_forward.py
+++ b/paddlespeech/s2t/modules/positionwise_feed_forward.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Positionwise feed forward layer definition."""
 import paddle
 from paddle import nn
diff --git a/paddlespeech/s2t/modules/subsampling.py b/paddlespeech/s2t/modules/subsampling.py
index 6b8c28c6a0f7d3927f75ea9088eea7d03451e99b..b60a6b1cdc70f1525fdf428d31b1dc0f1d50cf5c 100644
--- a/paddlespeech/s2t/modules/subsampling.py
+++ b/paddlespeech/s2t/modules/subsampling.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Subsampling layer definition."""
 from typing import Tuple
 
diff --git a/paddlespeech/s2t/training/extensions/evaluator.py b/paddlespeech/s2t/training/extensions/evaluator.py
index 9da0d731645ca6005fa917d433bca338685613c6..5989e313527fed1e52213a830d5710d316e16882 100644
--- a/paddlespeech/s2t/training/extensions/evaluator.py
+++ b/paddlespeech/s2t/training/extensions/evaluator.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 from typing import Dict
 
 import paddle
diff --git a/paddlespeech/s2t/training/extensions/extension.py b/paddlespeech/s2t/training/extensions/extension.py
index 02f924951304a5c83e4354297f12919033dc265b..1eb034273e5d45ea3a6dc36c174f226bce4a8f4b 100644
--- a/paddlespeech/s2t/training/extensions/extension.py
+++ b/paddlespeech/s2t/training/extensions/extension.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 PRIORITY_WRITER = 300
 PRIORITY_EDITOR = 200
 PRIORITY_READER = 100
diff --git a/paddlespeech/s2t/training/extensions/plot.py b/paddlespeech/s2t/training/extensions/plot.py
index 6fbb4d4dc7e40f61315173c4c04fb1d673f825c8..d2e5e321f8770d8f8501b187dc9a0feb5bf502e0 100644
--- a/paddlespeech/s2t/training/extensions/plot.py
+++ b/paddlespeech/s2t/training/extensions/plot.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 import copy
 import os
 
diff --git a/paddlespeech/s2t/training/extensions/snapshot.py b/paddlespeech/s2t/training/extensions/snapshot.py
index 753c7ec0ec93d76bc0435d1500a0eaf7a44f0826..fb4e80fee286cf085a3ce5418bf713ae2787f748 100644
--- a/paddlespeech/s2t/training/extensions/snapshot.py
+++ b/paddlespeech/s2t/training/extensions/snapshot.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 import os
 from datetime import datetime
 from pathlib import Path
diff --git a/paddlespeech/s2t/training/optimizer.py b/paddlespeech/s2t/training/optimizer.py
index 8ed30769f727c3345e5d5b304bd39923de4d3608..f0bcb313ed291ba4f3a6c12ec817a6bb533a33ca 100644
--- a/paddlespeech/s2t/training/optimizer.py
+++ b/paddlespeech/s2t/training/optimizer.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 from typing import Any
 from typing import Dict
 from typing import Text
diff --git a/paddlespeech/s2t/training/reporter.py b/paddlespeech/s2t/training/reporter.py
index 7afc33f38966529c75831d45443c848ea0c12839..22b2675211385a63ca1231067b885b78b37165e2 100644
--- a/paddlespeech/s2t/training/reporter.py
+++ b/paddlespeech/s2t/training/reporter.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 import contextlib
 import math
 from collections import defaultdict
diff --git a/paddlespeech/s2t/training/scheduler.py b/paddlespeech/s2t/training/scheduler.py
index f850f6f5026c64babb62fa8b666db484033e0064..732cbf0b5579ca21fc9b1ce67fa967361b7b6126 100644
--- a/paddlespeech/s2t/training/scheduler.py
+++ b/paddlespeech/s2t/training/scheduler.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 from typing import Any
 from typing import Dict
 from typing import Text
diff --git a/paddlespeech/s2t/training/triggers/compare_value_trigger.py b/paddlespeech/s2t/training/triggers/compare_value_trigger.py
index efb928e2c81b5100f2c42cdb41bbf32864da96a7..7c550268175a56ecf65aa522d9a7a6e4362f31dc 100644
--- a/paddlespeech/s2t/training/triggers/compare_value_trigger.py
+++ b/paddlespeech/s2t/training/triggers/compare_value_trigger.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 from ..reporter import DictSummary
 from .utils import get_trigger
 
diff --git a/paddlespeech/s2t/training/triggers/interval_trigger.py b/paddlespeech/s2t/training/triggers/interval_trigger.py
index 1e04afad8d52ba6a8a272edebfba7f09f9784723..14201d29cfc101263db51febb039a01e36bfbf1b 100644
--- a/paddlespeech/s2t/training/triggers/interval_trigger.py
+++ b/paddlespeech/s2t/training/triggers/interval_trigger.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 
 
 class IntervalTrigger():
diff --git a/paddlespeech/s2t/training/triggers/limit_trigger.py b/paddlespeech/s2t/training/triggers/limit_trigger.py
index ecd527ac5349486fa398c00e1171d8d1b51b293b..cd96040ef0bbc54c878ed9b194e10936eab4974f 100644
--- a/paddlespeech/s2t/training/triggers/limit_trigger.py
+++ b/paddlespeech/s2t/training/triggers/limit_trigger.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 
 
 class LimitTrigger():
diff --git a/paddlespeech/s2t/training/triggers/time_trigger.py b/paddlespeech/s2t/training/triggers/time_trigger.py
index e31179a9fd90c9fd337f656ca414f8b2dbf2940c..53c398d11ca7547f86f2445c2f6d0228a0ca2ecc 100644
--- a/paddlespeech/s2t/training/triggers/time_trigger.py
+++ b/paddlespeech/s2t/training/triggers/time_trigger.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 
 
 class TimeTrigger():
diff --git a/paddlespeech/s2t/training/updaters/standard_updater.py b/paddlespeech/s2t/training/updaters/standard_updater.py
index 83180a38d6e30500c23dc3b900655ce205baafd5..a686af743d5622f4adf642fd0878a9ab279b0133 100644
--- a/paddlespeech/s2t/training/updaters/standard_updater.py
+++ b/paddlespeech/s2t/training/updaters/standard_updater.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 from typing import Dict
 from typing import Optional
 
diff --git a/paddlespeech/s2t/training/updaters/trainer.py b/paddlespeech/s2t/training/updaters/trainer.py
index dcf844e360a11963ed0d4d875877df128011e60e..5a1295eb3ebfa51e48e566faed090b125b5cc143 100644
--- a/paddlespeech/s2t/training/updaters/trainer.py
+++ b/paddlespeech/s2t/training/updaters/trainer.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 import sys
 import traceback
 from collections import OrderedDict
diff --git a/paddlespeech/s2t/training/updaters/updater.py b/paddlespeech/s2t/training/updaters/updater.py
index ff8d925ffcf1525e75816f73355c8a92cf0cd4df..427722d2fe22606d8d94b733ab6bb22177d7b6a5 100644
--- a/paddlespeech/s2t/training/updaters/updater.py
+++ b/paddlespeech/s2t/training/updaters/updater.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 from dataclasses import dataclass
 
 import paddle
diff --git a/paddlespeech/s2t/transform/add_deltas.py b/paddlespeech/s2t/transform/add_deltas.py
index 4cab0084eac0019335783ef3cfa093e5220b2fed..0a2f34198fd7fbd0f0a17e90a8c69d5f17c32179 100644
--- a/paddlespeech/s2t/transform/add_deltas.py
+++ b/paddlespeech/s2t/transform/add_deltas.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import numpy as np
 
 
diff --git a/paddlespeech/s2t/transform/channel_selector.py b/paddlespeech/s2t/transform/channel_selector.py
index d985b482defd7a5792dff1a4a3fca21132756a78..bc8a14bf0273b1c4cc507aeeaa1ce7bb48800b34 100644
--- a/paddlespeech/s2t/transform/channel_selector.py
+++ b/paddlespeech/s2t/transform/channel_selector.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import numpy
 
 
diff --git a/paddlespeech/s2t/transform/cmvn.py b/paddlespeech/s2t/transform/cmvn.py
index 5d3185906f65b507ec6afcbec2ca4b2767b83164..749d5e187e585094a3f306b90b1cfec11fc9d580 100644
--- a/paddlespeech/s2t/transform/cmvn.py
+++ b/paddlespeech/s2t/transform/cmvn.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import io
 
 import h5py
diff --git a/paddlespeech/s2t/transform/functional.py b/paddlespeech/s2t/transform/functional.py
index e23d55f9d382c79e4cf05e5c95b07d4dff220c51..afbf4a59f82fe204b06a4f80396ec20243f01530 100644
--- a/paddlespeech/s2t/transform/functional.py
+++ b/paddlespeech/s2t/transform/functional.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import inspect
 
 from paddlespeech.s2t.transform.transform_interface import TransformInterface
diff --git a/paddlespeech/s2t/transform/perturb.py b/paddlespeech/s2t/transform/perturb.py
index f7e8bb764c1f972fb3ec8243185542a24de2434e..8671420c102061341aef104de981369e36d4dacc 100644
--- a/paddlespeech/s2t/transform/perturb.py
+++ b/paddlespeech/s2t/transform/perturb.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import librosa
 import numpy
 import scipy
diff --git a/paddlespeech/s2t/transform/spec_augment.py b/paddlespeech/s2t/transform/spec_augment.py
index 01ead8addb9f8a3c720b51848f9b1e6e95d26e2c..76e101848a4d949768ce3bdbca98cba083107baa 100644
--- a/paddlespeech/s2t/transform/spec_augment.py
+++ b/paddlespeech/s2t/transform/spec_augment.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Spec Augment module for preprocessing i.e., data augmentation"""
 import random
 
diff --git a/paddlespeech/s2t/transform/spectrogram.py b/paddlespeech/s2t/transform/spectrogram.py
index e63bd68030085cca745f7981eea30d4cd3bf6d9b..aeedf545bc8460af1b6e678e016fac38b2926fe1 100644
--- a/paddlespeech/s2t/transform/spectrogram.py
+++ b/paddlespeech/s2t/transform/spectrogram.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import librosa
 import numpy as np
 
diff --git a/paddlespeech/s2t/transform/transform_interface.py b/paddlespeech/s2t/transform/transform_interface.py
index 7ab29554e8f1d6bd158fc1f4126b74e55e1efc06..a7e04ffcf40db6c0cd94838d164e1c76b1f5a86e 100644
--- a/paddlespeech/s2t/transform/transform_interface.py
+++ b/paddlespeech/s2t/transform/transform_interface.py
@@ -11,7 +11,9 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-# TODO(karita): add this to all the transform impl.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
+
+
 class TransformInterface:
     """Transform Interface"""
 
diff --git a/paddlespeech/s2t/transform/transformation.py b/paddlespeech/s2t/transform/transformation.py
index d9bb7c1684ff0ac5c1ddfb10127b5bde332faac0..f0d1cd175cf1bd9f5783331753bfb22b7db938f8 100644
--- a/paddlespeech/s2t/transform/transformation.py
+++ b/paddlespeech/s2t/transform/transformation.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 """Transformation module."""
 import copy
 import io
@@ -23,8 +24,6 @@ import yaml
 
 from paddlespeech.s2t.utils.dynamic_import import dynamic_import
 
-# TODO(karita): inherit TransformInterface
-# TODO(karita): register cmd arguments in asr_train.py
 import_alias = dict(
     identity="paddlespeech.s2t.transform.transform_interface:Identity",
     time_warp="paddlespeech.s2t.transform.spec_augment:TimeWarp",
diff --git a/paddlespeech/s2t/transform/wpe.py b/paddlespeech/s2t/transform/wpe.py
index d82005f6473dba0f0a6cc4f3edd25992ecf4a751..463810ddafd6af6bd7d15997d252795d6f94bd0c 100644
--- a/paddlespeech/s2t/transform/wpe.py
+++ b/paddlespeech/s2t/transform/wpe.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 from nara_wpe.wpe import wpe
 
 
diff --git a/paddlespeech/s2t/utils/asr_utils.py b/paddlespeech/s2t/utils/asr_utils.py
index 6f86e56f75bb2b979c48f0fdddf8ca86e5130d0e..9184fd6af6c4046acbbe2e78346621f6eb25ae8b 100644
--- a/paddlespeech/s2t/utils/asr_utils.py
+++ b/paddlespeech/s2t/utils/asr_utils.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import json
 
 import numpy as np
@@ -18,7 +19,6 @@ import numpy as np
 __all__ = ["label_smoothing_dist"]
 
 
-# TODO(takaaki-hori): add different smoothing methods
 def label_smoothing_dist(odim, lsm_type, transcript=None, blank=0):
     """Obtain label distribution for loss smoothing.
 
diff --git a/paddlespeech/s2t/utils/check_kwargs.py b/paddlespeech/s2t/utils/check_kwargs.py
index 1ee7329bacd5fd0c7333cf28ce96eb1a74ad64c3..11214aac7370315fe1829e78161e998ea6f154d4 100644
--- a/paddlespeech/s2t/utils/check_kwargs.py
+++ b/paddlespeech/s2t/utils/check_kwargs.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import inspect
 
 
diff --git a/paddlespeech/s2t/utils/cli_readers.py b/paddlespeech/s2t/utils/cli_readers.py
index 010adb7a92f4277e9e5c39b0c64636063b7eefff..a1742d4f0859b28e55a7d69c262f9783a5a79ffd 100644
--- a/paddlespeech/s2t/utils/cli_readers.py
+++ b/paddlespeech/s2t/utils/cli_readers.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import io
 import logging
 import sys
diff --git a/paddlespeech/s2t/utils/cli_utils.py b/paddlespeech/s2t/utils/cli_utils.py
index f8e1d60bfe605001410869124b307f3d149fda68..8c3953d6936319a1fafeb98f5a459123aa19535a 100644
--- a/paddlespeech/s2t/utils/cli_utils.py
+++ b/paddlespeech/s2t/utils/cli_utils.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import sys
 from collections.abc import Sequence
 from distutils.util import strtobool as dist_strtobool
diff --git a/paddlespeech/s2t/utils/cli_writers.py b/paddlespeech/s2t/utils/cli_writers.py
index 5866a82eeb90503dca0c90d6d02262aeee6dd571..4fa7824e7617f93d6aee52d629644f8e0e14b49b 100644
--- a/paddlespeech/s2t/utils/cli_writers.py
+++ b/paddlespeech/s2t/utils/cli_writers.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 from pathlib import Path
 from typing import Dict
 
diff --git a/paddlespeech/s2t/utils/ctc_utils.py b/paddlespeech/s2t/utils/ctc_utils.py
index ff23350a3e38c95c92f470a169a39f74406df9db..5e5714469162af18245fcea7f43259a1caa6ce9d 100644
--- a/paddlespeech/s2t/utils/ctc_utils.py
+++ b/paddlespeech/s2t/utils/ctc_utils.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference wenet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 from typing import List
 
 import numpy as np
@@ -138,16 +139,6 @@ def forced_align(ctc_probs: paddle.Tensor, y: paddle.Tensor,
     return output_alignment
 
 
-# ctc_align(
-# self.model,
-# self.align_loader,
-# self.config.decoding.batch_size,
-# self.align_loader.collate_fn.stride_ms,
-# self.align_loader.collate_fn.vocab_list,
-# self.args.result_file,
-# )
-
-
 def ctc_align(model, dataloader, batch_size, stride_ms, token_dict,
               result_file):
     """ctc alignment.
diff --git a/paddlespeech/s2t/utils/dynamic_import.py b/paddlespeech/s2t/utils/dynamic_import.py
index ddf17afe9f10939acdcbff9c198cb6ae494764ee..9b415bb7ff20a35cf15005319b6dc92c18464a1d 100644
--- a/paddlespeech/s2t/utils/dynamic_import.py
+++ b/paddlespeech/s2t/utils/dynamic_import.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference espnet Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 import importlib
 import inspect
 from typing import Any
diff --git a/paddlespeech/t2s/training/extension.py b/paddlespeech/t2s/training/extension.py
index 07e92696e18ffcbdc74eee3b44434a30617e2e23..cc59e92226e2817e7f0f303afe2e19a792518e1b 100644
--- a/paddlespeech/t2s/training/extension.py
+++ b/paddlespeech/t2s/training/extension.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 from typing import Callable
 
 PRIORITY_WRITER = 300
diff --git a/paddlespeech/t2s/training/extensions/evaluator.py b/paddlespeech/t2s/training/extensions/evaluator.py
index 28249d096655f84d3a60becea38273b184d30140..3d17f70cd65ed3bd209387e81f3f65775fb86007 100644
--- a/paddlespeech/t2s/training/extensions/evaluator.py
+++ b/paddlespeech/t2s/training/extensions/evaluator.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 from typing import Dict
 
 import paddle
diff --git a/paddlespeech/t2s/training/extensions/snapshot.py b/paddlespeech/t2s/training/extensions/snapshot.py
index 2e4015969ed88d7a77f1df33b4362a291c4db963..f9b672687517d99bc3b4e188f9ebb9a4658bcfec 100644
--- a/paddlespeech/t2s/training/extensions/snapshot.py
+++ b/paddlespeech/t2s/training/extensions/snapshot.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 import logging
 import os
 from datetime import datetime
diff --git a/paddlespeech/t2s/training/reporter.py b/paddlespeech/t2s/training/reporter.py
index 013c754e3e494cd913fcd65b74c18a8b9643be2f..93c1e1776202d4be61fc249b17d61fc4d0558175 100644
--- a/paddlespeech/t2s/training/reporter.py
+++ b/paddlespeech/t2s/training/reporter.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 import contextlib
 import math
 from collections import defaultdict
diff --git a/paddlespeech/t2s/training/triggers/interval_trigger.py b/paddlespeech/t2s/training/triggers/interval_trigger.py
index 98c0368469898f4e46809cc2ae2b25b5c5271c47..a83139ba9e1e6560ac2841aecafae8713cfff370 100644
--- a/paddlespeech/t2s/training/triggers/interval_trigger.py
+++ b/paddlespeech/t2s/training/triggers/interval_trigger.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 
 
 class IntervalTrigger(object):
diff --git a/paddlespeech/t2s/training/triggers/limit_trigger.py b/paddlespeech/t2s/training/triggers/limit_trigger.py
index dd7a135e069c3323a07d042db12a5273dc185ce4..db1db774e9cadf15aa0a5625bbce5e3966c1f7b3 100644
--- a/paddlespeech/t2s/training/triggers/limit_trigger.py
+++ b/paddlespeech/t2s/training/triggers/limit_trigger.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 
 
 class LimitTrigger(object):
diff --git a/paddlespeech/t2s/training/triggers/time_trigger.py b/paddlespeech/t2s/training/triggers/time_trigger.py
index aff9382559048ae3e7d71f64bf0e7cc4304ed5ae..d7123524b30645935571739c8cac3d78f7d22079 100644
--- a/paddlespeech/t2s/training/triggers/time_trigger.py
+++ b/paddlespeech/t2s/training/triggers/time_trigger.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 
 
 class TimeTrigger(object):
diff --git a/paddlespeech/t2s/training/updater.py b/paddlespeech/t2s/training/updater.py
index 1db3d5f9ea6b93a49fb45cf68bd5183fdc95e156..a7ea9c2d386d338f8392f78a309233a16e781bc2 100644
--- a/paddlespeech/t2s/training/updater.py
+++ b/paddlespeech/t2s/training/updater.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 import logging
 from dataclasses import dataclass
 
diff --git a/paddlespeech/t2s/training/updaters/standard_updater.py b/paddlespeech/t2s/training/updaters/standard_updater.py
index 2d00d196f8dc9a09b3507e93fa86bef4dd6e7a8e..ecbe0e6a8a89db86da4a0031894a1a426cbe3c76 100644
--- a/paddlespeech/t2s/training/updaters/standard_updater.py
+++ b/paddlespeech/t2s/training/updaters/standard_updater.py
@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# Reference chainer MIT (https://opensource.org/licenses/MIT)
 import logging
 import time
 from typing import Dict