<xs:element name="Heading">
  <xs:sequence>
    <xs:element name="SubElementHeadings" minOccurs="0">
      <xs:sequence>
        <xs:element ref="Heading" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
    </xs:element>
  </xs:sequence>
  <xs:attribute name="Name" type="xs:string" use="required"/>
  <xs:attribute name="HeadingId" type="xs:string" use="optional"/>
  <xs:attribute name="IsSortedOn" type="xs:boolean" use="optional" default="false"/>
</xs:element>