<xsl:attribute name="mergekey">
<xsl:text>title </xsl:text>
<xsl:value-of select="marc:datafield[@tag='245']/marc:subfield[@code='a']"/>
- <xsl:value-of select="marc:datafield[@tag='245']/marc:subfield[@code='b']"/>
<xsl:text> author </xsl:text>
<xsl:value-of select="marc:datafield[@tag='100']/marc:subfield[@code='a']"/>
</xsl:attribute>
<xsl:value-of select="marc:datafield[@tag='245']/marc:subfield[@code='b']"/>
</pz:metadata>
+ <xsl:for-each select="marc:datafield[@tag='020']">
+ <pz:metadata type="isbn">
+ <xsl:value-of select="marc:subfield[@code='a']"/>
+ </pz:metadata>
+ </xsl:for-each>
+
<xsl:for-each select="marc:datafield[@tag='260']">
<pz:metadata type="date">
<xsl:value-of select="marc:subfield[@code='c']"/>