diff --git a/README.md b/README.md
index cfafb24..9061cef 100644
--- a/README.md
+++ b/README.md
@@ -23,4 +23,8 @@ http://stackoverflow.com/questions/2391679/why-do-we-need-virtual-functions-in-c
 inheritance and default constructor
 http://stackoverflow.com/questions/4352169/default-constructor-for-an-inherited-class
 
+detect unused #include files
+http://stackoverflow.com/questions/74326/how-should-i-detect-unnecessary-include-files-in-a-large-c-project
+http://stackoverflow.com/questions/614794/c-c-detecting-superfluous-includes
+
 ~~~