diff --git a/docs/admin.rst b/docs/admin.rst
index 3da96d6..7de3048 100644
--- a/docs/admin.rst
+++ b/docs/admin.rst
@@ -86,10 +86,12 @@ The models are taken from :ref:`advanced-features`.
 
 
     class ModelBAdmin(ModelAChildAdmin):
+        base_model = ModelB
         # define custom features here
 
 
     class ModelCAdmin(ModelBAdmin):
+        base_model = ModelC
         # define custom features here