Other subfields should be also visible: $a $x and $z
<xsl:if test="marc:datafield[@tag=866]">
<span class="results_summary holdings_note"><span class="label">Holdings Note: </span>
<xsl:for-each select="marc:datafield[@tag=866]">
- <xsl:value-of select="marc:subfield[@code='z']"/>
+ <xsl:value-of select="marc:subfield[@code='a']"/>
<xsl:choose><xsl:when test="position()=last()"><xsl:text>.</xsl:text></xsl:when><xsl:otherwise><xsl:text>; </xsl:text></xsl:otherwise></xsl:choose>
</xsl:for-each>
</span>