1<grammar xmlns="http://relaxng.org/ns/structure/1.0"> 2 3 <start> 4 <element name="addressBook"> 5 <zeroOrMore> 6 <element name="card"> 7 <ref name="card.attlist"/> 8 </element> 9 </zeroOrMore> 10 </element> 11 </start> 12 13 <define name="card.attlist" combine="interleave"> 14 <attribute name="name"> 15 <text/> 16 </attribute> 17 </define> 18 19 <define name="card.attlist" combine="interleave"> 20 <attribute name="email"> 21 <text/> 22 </attribute> 23 </define> 24 25</grammar> 26