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