1<grammar xmlns="http://relaxng.org/ns/structure/1.0">
2
3  <start>
4    <element name="addressBook">
5      <zeroOrMore>
6	<element name="card">
7	  <ref name="card.attlist"/>
8	</element>
9      </zeroOrMore>
10    </element>
11  </start>
12
13  <define name="card.attlist" combine="interleave">
14    <attribute name="name">
15      <text/>
16    </attribute>
17  </define>
18
19  <define name="card.attlist" combine="interleave">
20    <attribute name="email">
21      <text/>
22    </attribute>
23  </define>
24
25</grammar>
26