Index: lib/redcloth3.rb
===================================================================
--- lib/redcloth3.rb	(revision 2316)
+++ lib/redcloth3.rb	(working copy)
@@ -792,7 +792,7 @@
             (?:\(([^)]+?)\)(?="))?     # $title
             ":
             (                          # $url
-            (\/|https?:\/\/|s?ftps?:\/\/|www\.)
+            (\/|https?:\/\/|s?ftps?:\/\/|[Nn]otes:\/\/|www\.)
             [\w\/]\S+?
             )               
             (\/)?                      # $slash