<xsl:template match="catalog">
<head>
<title><xsl:value-of select="category"/></title>
</head>
<body>
<h1><xsl:value-of select="category"/></h1>
<xsl:apply-templates select="composer">
<xsl:sort select="name/last_name"/>
</xsl:apply-templates>
<hr/>
Copyright <xsl:value-of select="copyright"/><br/>
Last Modified: <xsl:value-of select="last_updated"/><br/>
<xsl:apply-templates select="maintainer"/>
</body>
</xsl:template>
The select attribute provides the key to sort by
Must be a child of xsl:apply-templates or xsl:for-each