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