<element name="addressBook" xmlns="http://relaxng.org/ns/structure/1.0">

  <zeroOrMore>

    <element name="card">

      <element name="name">

        <text/>

      </element>

      <element name="email">

        <text/>

      </element>

      <optional>

	<element name="note">

	  <text/>

	</element>

      </optional>

    </element>

  </zeroOrMore>

</element>