<grammar xmlns="http://relaxng.org/ns/structure/1.0" ns="urn:test:simple.rng">

  <include href="include.rng" />

  <define name="target1">
    <grammar>
      <include href="include.rng">
        <define name="included">
          <parentRef name="included" />
        </define>
      </include>
    </grammar>
  </define>
</grammar>