xmlns:a="http://www.example.com/address"

         xmlns="http://relaxng.org/ns/structure/1.0">

  <zeroOrMore>

    <element name="ab:card">

      <element name="a:name">

        <text/>

      </element>

      <element name="a:email">

        <text/>

      </element>

    </element>

  </zeroOrMore>

</element>