<?xml version="1.0"?> <Foo xmlns="urn:test:foo" xmlns:foo="urn:test:foo" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:test:foo idc-keyref_1.xsd"> <Def> <Link foo:linkKey="L4"/> </Def> <Ref foo:linkRef="L4"/> </Foo>