ISO/TS 10303-1275:2004

ISO/TS 10303-1275:2004 specifies the application module for External class. The following are within the scope of ISO/TS 10303-1275:2004: The identification of a class that is external to a data exchange file; The identification of an external class library that is not in an exchange file and holds the definition for classes used in the exchange file; A reference to a class in an external class library.