diff --git a/source/api_reference/index.rst b/source/api_reference/index.rst
index d19132e3c665150fc892ca9889f4af620194469d..33ca65edf517c6ab97c0bc6b230d5c61a06fd6d8 100644
--- a/source/api_reference/index.rst
+++ b/source/api_reference/index.rst
@@ -21,3 +21,5 @@ API Reference
     data.rst
     transpiler.rst
     recordio_writer.rst
+    backward.rst
+    average.rst