<?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> 