Hello Eve, I guess, we can use that construct for the restiction of named version although. I will try an example for that. The CCT itself is an Identifier.Type like the following structure: <!-- ===== CCT: Identifier. Type =====--> <xsd:complexType name="IdentifierType"> <xsd:simpleContent> <xsd:extension base="xsd:token"> <xsd:attribute name="schemeId" type="xsd:token" use="optional"/> <xsd:attribute name="schemeName" type="xsd:token" use="optional"/> <xsd:attribute name="schemeAgencyId" type="xsd:token" use="optional"/> <xsd:attribute name="schemeAgencyName" type="xsd:token" use="optional"/> <xsd:attribute name="schemeVersionId" type="xsd:token" use="optional"/> <xsd:attribute name="schemeDataURI" type="xsd:token" use="optional"/> <xsd:attribute name="schemeURI" type="xsd:token" use="optional"/> <xsd:attributeGroup ref="cct:commonAttributes"/> </xsd:extension> </xsd:simpleContent> </xsd:complexType> And based on this CCT, I can generate a named complexType for a BCC. This BCC representing a "Article. Identification. Identifier", for example. This BCC do not need all attributes and have a max. length of 20 characters, because can be the maximum length of all different identifiers for articles. Therefore you need some restrictions in this named complexType, like the following example: <!-- ===== BCC: Article. Identification. Identifier =====--> <xsd:complexType name="ArticleIdentifier"> <xsd:simpleContent> <xsd:restriction base="cct:IdentifierType"> <xsd:maxLength value="20"/> <xsd:attribute name="schemeName" use="prohibited"/> <xsd:attribute name="schemeAgencyName" use="prohibited"/> </xsd:restriction> </xsd:simpleContent> </xsd:complexType> I hope, you' re agree with that. Kind regards, Gunther