diff --git a/AH-TreeReader/notes.txt b/AH-TreeReader/notes.txt
index 7a8b511..4f44a8b 100644
--- a/AH-TreeReader/notes.txt
+++ b/AH-TreeReader/notes.txt
@@ -9,4 +9,6 @@ https://gitlab.com/tliero/burp/blob/master/Modern%20Web%20Applications.pptx
 https://en.wikipedia.org/wiki/Representational_state_transfer
 - POST for retrieval?
 - ID via form data?
-- malformed XML
\ No newline at end of file
+- malformed XML
+
+https://martinfowler.com/articles/richardsonMaturityModel.html
\ No newline at end of file