More source links.
diff --git a/Doc/library/cgi.rst b/Doc/library/cgi.rst
index 8c75517..1e2498d 100644
--- a/Doc/library/cgi.rst
+++ b/Doc/library/cgi.rst
@@ -13,6 +13,10 @@
    single: URL
    single: Common Gateway Interface
 
+**Source code:** :source:`Lib/cgi.py`
+
+--------------
+
 Support module for Common Gateway Interface (CGI) scripts.
 
 This module defines a number of utilities for use by CGI scripts written in