DocumentGroup 

To provide document specific data, such as document
numbers

Attribute Group Information

Attributes

QName Type Fixed Default Use Inheritable Annotation
Mask xs:string optional 
The mask used to validate the format of a ticket
number
Number xs:string optional 
To specify the unique document number. Additional references would
be entered in codes.

Source 

<xs:attributeGroup name="DocumentGroup">
  <xs:annotation>
    <xs:documentation>To provide document specific data, such as document numbers</xs:documentation>
  </xs:annotation>
  <xs:attribute name="Number" type="xs:string" use="optional">
    <xs:annotation>
      <xs:documentation>To specify the unique document number. Additional references would be entered in codes.</xs:documentation>
    </xs:annotation>
  </xs:attribute>
  <xs:attribute name="Mask" type="xs:string" use="optional">
    <xs:annotation>
      <xs:documentation>The mask used to validate the format of a ticket number</xs:documentation>
    </xs:annotation>
  </xs:attribute>
</xs:attributeGroup>