he nodeset extension can be used as an XSLTC extension function in the namespace
    <CODE><FONT face="courier, monospaced">http://xml.apache.org/xalan/xsltc</FONT></CODE>, a Xalan-Java extension function in the namespace
    <CODE><FONT face="courier, monospaced">http://xml.apache.org/xalan</FONT></CODE>, an EXSLT extension function in the namespace 
    <CODE><FONT face="courier, monospaced">http://exslt.org/common</FONT></CODE> or as a standard XPATH function. When it is used as
    an EXSLT extension fu