diff --git a/ppdet/modeling/backbones/swin_transformer.py b/ppdet/modeling/backbones/swin_transformer.py
index 73da7958f0422d3f0e4156a8dda938eedbc12def..027e4f67afdd84822c861de32824002d383591ba 100644
--- a/ppdet/modeling/backbones/swin_transformer.py
+++ b/ppdet/modeling/backbones/swin_transformer.py
@@ -11,6 +11,11 @@
 # 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.
+"""
+This code is based on https://github.com/microsoft/Swin-Transformer/blob/main/models/swin_transformer.py
+Ths copyright of microsoft/Swin-Transformer is as follows:
+MIT License [see LICENSE for details]
+"""
 
 import paddle
 import paddle.nn as nn
diff --git a/ppdet/modeling/heads/sparsercnn_head.py b/ppdet/modeling/heads/sparsercnn_head.py
index 30270b6ecc9f827284fed11b4349b1e3787dfb81..377cf27fc6e10ff62b06345c7f639f064c05e5e7 100644
--- a/ppdet/modeling/heads/sparsercnn_head.py
+++ b/ppdet/modeling/heads/sparsercnn_head.py
@@ -11,6 +11,11 @@
 # 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.
+"""
+This code is based on https://github.com/PeizeSun/SparseR-CNN/blob/main/projects/SparseRCNN/sparsercnn/head.py
+Ths copyright of PeizeSun/SparseR-CNN is as follows:
+MIT License [see LICENSE for details]
+"""
 
 from __future__ import absolute_import
 from __future__ import division
diff --git a/ppdet/modeling/initializer.py b/ppdet/modeling/initializer.py
index ae0bc4287dabe8ded379063a0282a1a99096ed22..b7a135dcca7309be09fa4819e21d77a02d332d57 100644
--- a/ppdet/modeling/initializer.py
+++ b/ppdet/modeling/initializer.py
@@ -11,6 +11,10 @@
 # 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.
+"""
+This code is based on https://github.com/pytorch/pytorch/blob/master/torch/nn/init.py
+Ths copyright of pytorch/pytorch is a BSD-style license, as found in the LICENSE file.
+"""
 
 import math
 import numpy as np
diff --git a/ppdet/modeling/losses/sparsercnn_loss.py b/ppdet/modeling/losses/sparsercnn_loss.py
index d8fc3d117b499d6ca32ab8275b5dc1f8ba86cae5..2d36b21a2302d6c070728cfb4a213c09232f1853 100644
--- a/ppdet/modeling/losses/sparsercnn_loss.py
+++ b/ppdet/modeling/losses/sparsercnn_loss.py
@@ -11,6 +11,11 @@
 # 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.
+"""
+This code is based on https://github.com/PeizeSun/SparseR-CNN/blob/main/projects/SparseRCNN/sparsercnn/loss.py
+Ths copyright of PeizeSun/SparseR-CNN is as follows:
+MIT License [see LICENSE for details]
+"""
 
 from __future__ import absolute_import
 from __future__ import division