<element name=“addressBook” xmlns=“relaxng.org/ns/structure/1.0”>

<zeroOrMore>
  <element name="card">
    <choice>
      <attribute name="name">
        <text/>
      </attribute>
      <group>
        <attribute name="givenName">
          <text/>
        </attribute>
        <attribute name="familyName">
          <text/>
        </attribute>
      </group>
    </choice>
    <attribute name="email">
      <text/>
    </attribute>
  </element>
</zeroOrMore>

</element>