diff --git a/README.md b/README.md
index 52b0b0ff7866fc41c0986ff0a4813ae3d15d9982..11c28935ebc9b6c941aa1f4f1208551a2a53d6a9 100644
--- a/README.md
+++ b/README.md
@@ -118,6 +118,7 @@ The `csst_proto` uses an awesome algorithm based on `numpy.ndarray` indices to f
 - Numpydoc: https://numpydoc.readthedocs.io/en/latest/format.html
   - for C: https://peps.python.org/pep-0007/
   - for Python: https://peps.python.org/pep-0008/
+    - example.py: https://numpydoc.readthedocs.io/en/latest/example.html#example
 - `unittest`: https://docs.python.org/3.8/library/unittest.html
 - gitlab CI/CD pipeline: https://docs.gitlab.com/ee/ci/pipelines/
 - gitlab runners: https://docs.gitlab.com/runner/
diff --git a/examples/how_to_write_docstring.py b/examples/how_to_write_docstring.py
index 2b7a6ffc15b93c748474803f079857710f0636c8..8f75b669a76bc2fc697bfec80f6766d1a9f98c32 100644
--- a/examples/how_to_write_docstring.py
+++ b/examples/how_to_write_docstring.py
@@ -34,5 +34,10 @@ def cos(x: float = 0.) -> float:
     Notes
     -----
     this function is a warpper of `numpy.cos()`
+
+    Conf
+    ----
+    https://numpydoc.readthedocs.io/en/latest/example.html#example
+
     """
     return np.cos(x)