Update links.md

Author: stevekrouse

links.md

@@ -57,7 +57,7 @@ title: Link Research
 * [Type Systems for Beginners](https://gilbert.ghost.io/type-systems-for-beginners-an-introduction/)
 * [Types, Logic, Semantics, and Verification](https://www.cs.uoregon.edu/research/summerschool/summer15/curriculum.html)
 * [Framer 3](https://www.producthunt.com/posts/framer-3)
-* 
+* https://en.wikipedia.org/wiki/Prograph
 
 ## Researched