diff --git a/helpers/app-store/genres.js b/helpers/app-store/genres.js
index ab11d51..2e8210a 100644
--- a/helpers/app-store/genres.js
+++ b/helpers/app-store/genres.js
@@ -1,3 +1,4 @@
+// Source 1: https://42matters.com/docs/app-market-data/ios/apps/appstore-genres
 export default {
     '0':    ['Mobile Software Application'],
     '6018': ['Book'],