final official link to webkit appearance values

frameworks/compass/stylesheets/compass/css3/_appearance.scss

@@ -5,7 +5,8 @@
 //
 // There is no official list of accepted values, but you might check these source:
 //   Mozilla : https://developer.mozilla.org/en/CSS/-moz-appearance
-//   Webkit  : http://developer.apple.com/library/safari/#documentation/appleapplications/reference/safaricssref/articles/standardcssproperties.html
+//   Webkit  : http://code.google.com/p/webkit-mirror/source/browse/Source/WebCore/css/CSSValueKeywords.in?spec=svnf1aea559dcd025a8946aa7da6e4e8306f5c1b604&r=63c7d1af44430b314233fea342c3ddb2a052e365
+//   (search for 'appearance' within the page)
 
 @mixin appearance($ap) {
   $ap: unquote($ap);