1<element name="addressBook" xmlns="http://relaxng.org/ns/structure/1.0">
2  <zeroOrMore>
3    <element name="card">
4      <element name="name">
5        <text/>
6      </element>
7      <element name="email">
8        <text/>
9      </element>
10      <optional>
11	<element name="note">
12	  <externalRef href="inline.rng"/>
13	</element>
14      </optional>
15    </element>
16  </zeroOrMore>
17</element>
18