You don't want to do that as you'll get a type error as doc() doesn't
return element nodes. Also it's unnecessarily verbose as you don't need
an xsLsequence you can just use select on the xsl:variable

 <xsl:variable name="bibrecord"
  select="doc(concat(&quot;http://localhost:8080/exist/servlet/db/mods?
  &quot;,

But if you only use this variable in one place, as input to your sorting
function you don't need a variable at all, you can just inline teh
expression.

	-	flatfile, where the data is in a local xml file and I just use xpath
	-	exist-xmldb, where data is on a server, and I access it with xquery
	-	sru, as above, but with another query language