Do you know how to process a list ? id=123,456,789

This how I would process one ID 
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:param name="muid"/>
<xsl:template match="/">
<xsl:output method="html"/>
<PreMedlineCitationSet>
<xsl:copy-of select="//MedlineCitation[MedlineID='$muid']" />
</PreMedlineCitationSet>
</xsl:template>
</xsl:stylesheet>


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list