diff --git a/model_data/simulation_system/app.py b/model_data/simulation_system/app.py
index ab687d74..545fae16 100644
--- a/model_data/simulation_system/app.py
+++ b/model_data/simulation_system/app.py
@@ -170,6 +170,9 @@ BUILT_FORM_REMAP = {
 def app():
     # Get all the files in the directory
 
+    # Data glossary:
+    # https://epc.opendatacommunities.org/docs/guidance#glossary
+
     directories = list_subdirectories(DATA_DIRECTORY)
 
     dataset = []