diff --git a/README.md b/README.md
index 8062a85..3558dad 100644
--- a/README.md
+++ b/README.md
@@ -82,4 +82,5 @@ https://github.com/gzc/CLRS
 TO look at:
 ~~~
 https://github.com/Mooophy/Cpp-Primer
+https://graphics.stanford.edu/~seander/bithacks.html
 ~~~