Addressing in external documents

      <xsl:stylesheet
                  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                  version="2.0">
            <xsl:output  method="xml"
                        indent="yes"
                        omit-xml-declaration="yes"/>

            <xsl:template  match="/aaa">
                  <xxx>
                        <xsl:value-of  select="document('ext1.xml')/rrr/ccc/@y"/>
                  </xxx>
            </xsl:template>

      </xsl:stylesheet>

      <aaa/>

      <rrr>
            <ccc  y="222"/>
      </rrr>

      <xxx>222</xxx>