[core] Add links to CommonJS and AMD module system docs

src/yui/docs/es6-modules.mustache

@@ -90,8 +90,12 @@ disadvantages:
     tools to build your project's files, then using ES6 syntax should easily tie
     into the process you already have to get your application running.</li>
     <li>It allows you to write your code in one format and transpile it to
-    different module formats including CommonJS, AMD and YUI modules.</li>
-    <li><a href="http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/">
+    different module formats including
+    <a href="http://nodejs.org/api/modules.html">CommonJS</a>,
+    <a href="http://know.cujojs.com/tutorials/modules/authoring-amd-modules">
+    AMD</a> and YUI modules.</li>
+    <li>
+    <a href="http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/">
     Sourcemaps</a> allow you to debug using the new syntax, so the difference
     between all the different underlying module systems is hidden by the
     developer tools.</li>