1<!DOCTYPE root [ 2 <!ATTLIST x id ID #IMPLIED> 3]> 4<root xmlns:xi="http://www.w3.org/2001/XInclude" xml:base="http://www.example.org/"> 5<xi:include href="" xpointer="foo"/> 6<x id="foo"> 7 <xi:include href="" xpointer="bar"/> 8</x> 9<x id="bar"/> 10</root>