i've this xsl file suggested by mikael kay that doesn't works to change my xml that follows the xsl file. the result that i wolud obtain is posted to the end. XSL file <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet exclude-result-prefixes="#all" version="2.0" xmlns:mets="http://www.loc.gov/METS/" xmlns:mix="http://www.loc.gov/mix/" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:rd="http://cosimo.stanford.edu/sdr/metsrights/" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:f="http://example.com/f"> <xsl:output indent="yes" method="xml"/> <xsl:template match="@* | node()"> <xsl:copy> <xsl:apply-templates select="@*, node()"/> </xsl:copy> </xsl:template> <xsl:variable name="g" select="//mets:div[matches(@LABEL, '^Pagina [0-9]+$')]"/> <xsl:template match="*[. intersect $g]/@LABEL"> <xsl:variable name="n" select="f:index-of-node($g, ..)"/> <xsl:attribute name="LABEL" select="concat('Carta ', if ($n mod 2 = 0) then concat(($n + 1) idiv 2, 'v') else concat(($n + 1) idiv 2, 'r'))"/> </xsl:template> <xsl:function name="f:index-of-node" as="xs:integer*"> <xsl:param name="nodes" as="node()*"/> <xsl:param name="node" as="node()"/> <xsl:sequence select="1 to count($nodes)[subsequence($nodes, ., 1) is $node]"/> </xsl:function> </xsl:stylesheet> XML file <mets:div LABEL="Canto VI" ORDER="8" ORDERLABEL="1"> <mets:div LABEL="Pagina 56"> <mets:fptr FILEID="file.00059"/> </mets:div> <mets:div LABEL="Pagina 57"> <mets:fptr FILEID="file.00060"/> </mets:div> <mets:div LABEL="Pagina 58"> <mets:fptr FILEID="file.00061"/> </mets:div> <mets:div LABEL="Pagina 59"> <mets:fptr FILEID="file.00062"/> </mets:div> <mets:div LABEL="Pagina 60"> <mets:fptr FILEID="file.00063"/> </mets:div> <mets:div LABEL="Pagina 61"> <mets:fptr FILEID="file.00064"/> </mets:div> <mets:div LABEL="Pagina 62"> <mets:fptr FILEID="file.00065"/> </mets:div> <mets:div LABEL="Pagina 63"> <mets:fptr FILEID="file.00066"/> </mets:div> <mets:div LABEL="Pagina 64"> <mets:fptr FILEID="file.00067"/> </mets:div> <mets:div LABEL="Pagina 65"> <mets:fptr FILEID="file.00068"/> </mets:div> <mets:div LABEL="Pagina 66"> <mets:fptr FILEID="file.00069"/> </mets:div> </mets:div> XML that i would obtain <mets:div LABEL="Canto XI"> <mets:div LABEL="Pagina 59"> <mets:fptr FILEID="file.00116"/> </mets:div> <mets:div LABEL="Carta [59v]" ORDER="2" ORDERLABEL="114"> <mets:fptr FILEID="file.00117"/> </mets:div> <mets:div LABEL="Carta [60r]" ORDER="3" ORDERLABEL="115"> <mets:fptr FILEID="file.00118"/> </mets:div> <mets:div LABEL="Carta [60v]" ORDER="4" ORDERLABEL="116"> <mets:fptr FILEID="file.00119"/> </mets:div> <mets:div LABEL="Carta [61r]" ORDER="5" ORDERLABEL="117"> <mets:fptr FILEID="file.00120"/> </mets:div> <mets:div LABEL="Carta [61v]" ORDER="6" ORDERLABEL="118"> <mets:fptr FILEID="file.00121"/> </mets:div> <mets:div LABEL="Carta [62r]" ORDER="7" ORDERLABEL="119"> <mets:fptr FILEID="file.00122"/> </mets:div> <mets:div LABEL="Carta [62v]" ORDER="8" ORDERLABEL="120"> <mets:fptr FILEID="file.00123"/> </mets:div> <mets:div LABEL="Carta [63r]" ORDER="9" ORDERLABEL="121"> <mets:fptr FILEID="file.00124"/> </mets:div> <mets:div LABEL="Carta [63v]" ORDER="10" ORDERLABEL="122"> <mets:fptr FILEID="file.00125"/> </mets:div> <mets:div LABEL="Carta [64r]" ORDER="11" ORDERLABEL="123"> <mets:fptr FILEID="file.00126"/> </mets:div> </mets:div>