1<element name="ab:addressBook" xmlns:ab="http://www.example.com/addressBook"
2                               xmlns:a="http://www.example.com/address"
3         xmlns="http://relaxng.org/ns/structure/1.0">
4  <zeroOrMore>
5    <element name="ab:card">
6      <element name="a:name">
7        <text/>
8      </element>
9      <element name="a:email">
10        <text/>
11      </element>
12    </element>
13  </zeroOrMore>
14</element>
15