Working with 2 versions of jquery in the same page

<script src="jQuery1.3.js"></script>
<script>
var jq13 = jQuery.noConflict(true);
</script>

<!-- original author's jquery version -->
<script src="jQuery1.2.3.js"></script>

//Fixed rest of the files with specific version
(function($) {
...
})(jq13);