1<grammar xmlns="http://relaxng.org/ns/structure/1.0"> 2 3 <include href="addressBook.rng"> 4 5 <define name="cardContent"> 6 <element name="name"> 7 <text/> 8 </element> 9 <element name="emailAddress"> 10 <text/> 11 </element> 12 </define> 13 14 </include> 15 16</grammar> 17