diff --git a/readme.md b/readme.md
index a8c5e88..3a192b9 100644
--- a/readme.md
+++ b/readme.md
@@ -289,3 +289,4 @@ class Functor f where
 - [Haskell - Wiki](https://wiki.haskell.org/Haskell)
 - [Haskell - Wikibooks](https://en.wikibooks.org/wiki/Haskell)
 - [hemanth/functional-programming-jargon](https://github.com/hemanth/functional-programming-jargon).
+- [Wolfram MathWorld](http://mathworld.wolfram.com)