diff --git a/core/todo.txt b/core/todo.txt
index f4f61fb54..cb6326d90 100644
--- a/core/todo.txt
+++ b/core/todo.txt
@@ -20,7 +20,7 @@ _   http://processing.org/discourse/yabb/YaBB.cgi?board=Proce55ing_software_bugs
 _ polygon z-order with alpha in opengl
 _   at least add it to the faq, or this would be a test case w/ the sorting
 _   http://dev.processing.org/bugs/show_bug.cgi?id=176
-
+_   http://www.opengl.org/resources/tutorials/advanced/advanced97/notes/node112.html
 _ lookat is now camera(), but not fixed in the docs
 _   add notes to the faq about the camera changes on the changes page