supplies a string representing a regular expression providing additional constraints on the strings used to represent values of this datatype  | 
                           
| Element | tei:dataRef | 
<xs:attribute name="restriction" type="xs:token"> <xs:annotation> <xs:documentation>supplies a string representing a regular expression providing additional constraints on the strings used to represent values of this datatype</xs:documentation> </xs:annotation> </xs:attribute>  |