1<rng:element name="addressBook" xmlns:rng="http://relaxng.org/ns/structure/1.0">
2  <rng:zeroOrMore>
3    <rng:element name="card">
4      <rng:element name="name">
5        <rng:text/>
6      </rng:element>
7      <rng:element name="email">
8        <rng:text/>
9      </rng:element>
10    </rng:element>
11  </rng:zeroOrMore>
12</rng:element>
13