Re: multi-document question

But you are using xml output in which case there are only five entities
defined. (lt gt apos quot and amp) If your character data includes a <
or & then most systems will use a lt or amp entity (as opposed to
the alternative of a numeric character reference). Clearly a <
character can not be linearised as < as it would be taken as markup.

   <xsl:template match="mods">
	<saxon:output href="{identifier[@type='citekey']}.mods" method="xml">
        <xsl:copy>
	   <xsl:copy-of select="node()|@*"/>
        </xsl:copy>
	</saxon:output>
   </xsl:template>