diff --git a/less/responsive-utilities.less b/less/responsive-utilities.less
index abbeeeb43d..b1db31d7bf 100644
--- a/less/responsive-utilities.less
+++ b/less/responsive-utilities.less
@@ -15,6 +15,7 @@
 //
 // Issue: https://github.com/twbs/bootstrap/issues/10497
 // Docs: http://getbootstrap.com/getting-started/#support-ie10-width
+// Source: http://timkadlec.com/2013/01/windows-phone-8-and-device-width/
 // Source: http://timkadlec.com/2012/10/ie10-snap-mode-and-responsive-design/
 
 @-ms-viewport {