diff --git a/doc/api.rst b/doc/api.rst
index 85c89e3e9f2461a63be14e3b0865221b8aedb517..957e50a21fc2af3199323ea18f9b78abf6298492 100644
--- a/doc/api.rst
+++ b/doc/api.rst
@@ -22,6 +22,10 @@ API
    :members:
    :undoc-members:
 
+.. automodule:: usadelndsoc.matsubara
+   :members:
+   :undoc-members:
+
 .. py:data:: usadelndsoc.logger
 
    `logging` instance used.