Multiple versions of jQuery on the same page

Layout.html

<script type='text/javascript' src='@Url.Content( "~/Scripts/jquery-1.5.1.js" )'></script>
<script type="text/javascript">
    $(selector).dosome(); // for use 1.5.1 jquery
</script>

PartialView.html

<!-- if we have layout with some jquery version -->
<script type="text/javascript" src='@Url.Content( "~/Scripts/jquery-1.6.4.js" )'></script>
<script type="text/javascript">
    // create this naming for Jquery 1.6.4 version
    var $j6 = $.noConflict(true);
    
    // for use 1.6.4 jquery:
    $j6(selector).dosome();
    
    // for use default jquery version (1.5.1)
    $(selector).dosome();
</script>

<!-- |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| -->
<!-- we can include other version jquery after 1.6.4 (if we haven't layout) -->
<script type="text/javascript" src='@Url.Content( "~/Scripts/jquery-1.6.4.js" )'></script>
<script type="text/javascript">
    // create this naming for Jquery 1.6.4 version
    var $j6 = $.noConflict(true);
</script>
<script type='text/javascript' src='@Url.Content( "~/Scripts/jquery-1.5.1.js" )'></script>
<script type="text/javascript">
    // for use 1.6.4 jquery:
    $j6(selector).dosome();
    
    // for use default jquery version (1.5.1)
    $(selector).dosome();
</script>