P5: Guidelines for Electronic Text Encoding and Interchange

<rng:element name="objectDesc">
<rng:ref name="att.global.attributes"/>
<rng:optional>
 <rng:attribute name="form">
  <rng:ref name="data.enumerated"/>
 </rng:attribute>
</rng:optional>
<rng:choice>
 <rng:oneOrMore>
  <rng:ref name="model.pLike"/>
 </rng:oneOrMore>
 <rng:group>
  <rng:optional>
   <rng:ref name="supportDesc"/>
  </rng:optional>
  <rng:optional>
   <rng:ref name="layoutDesc"/>
  </rng:optional>
 </rng:group>
</rng:choice>
</rng:element>

element objectDesc
{
   att.global.attributes,
   attribute form { data.enumerated }?,
   ( model.pLike+ | ( supportDesc?, layoutDesc? ) )
}