<grammar xmlns=“relaxng.org/ns/structure/1.0”>
<start> <element name="addressBook"> <zeroOrMore> <element name="card"> <ref name="card.attlist"/> </element> </zeroOrMore> </element> </start> <define name="card.attlist" combine="interleave"> <attribute name="name"> <text/> </attribute> </define> <define name="card.attlist" combine="interleave"> <attribute name="email"> <text/> </attribute> </define>
</grammar>