diff --git a/calculator.css b/calculator.css
index 7ac0c71..680f94e 100644
--- a/calculator.css
+++ b/calculator.css
@@ -1,3 +1,5 @@
+/*See https://artofproblemsolving.com/community/c726379 for example usage*/
+
 @import url("https://fonts.googleapis.com/css?family=Titillium+Web:100,200,300,375,400,500,600,700,800,900");
 @import url("https://fonts.googleapis.com/css?family=VT323:100,200,300,375,400,500,600,700,800,900");
 body {