<xs:simpleType name="osisWorkPrefix"> <xs:restriction base="xs:string"> <xs:pattern value="((//((\p{L}|\p{N}|_|-|\.|:)+))(/(\p{L}|\p{N}|_|-|\.|:)+)?(/@(\p{L}|\p{N}|_|-|\.|:)+))"/> </xs:restriction> </xs:simpleType>