diff --git a/doc/sources/conf.py b/doc/sources/conf.py
index 6a9c11ebd..6b2f629cb 100644
--- a/doc/sources/conf.py
+++ b/doc/sources/conf.py
@@ -23,7 +23,9 @@ sys.path.insert(0, os.path.abspath('sphinxext'))
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ['autodoc', 'sphinx.ext.todo', 'preprocess', 'sphinx.ext.ifconfig']
+extensions = [
+    'autodoc', 'sphinx.ext.todo', 'preprocess', 'sphinx.ext.ifconfig',
+    'sphinx.ext.viewcode']
 
 # Todo configuration
 todo_include_todos = True