<grammar xmlns=“relaxng.org/ns/structure/1.0”>
<define name=“cell.content”>
<notAllowed/>
</define>
<start>
<element name="table"> <oneOrMore> <element name="tr"> <oneOrMore> <element name="td"> <ref name="cell.content"/> </element> </oneOrMore> </element> </oneOrMore> </element>
</start>
</grammar>