Three integrated EXPRESS information models are defined in ISO 13584-24:2003. They permit respectively the exchange of libraries which consist either of definitions of families of parts, representations of families of parts or definitions of new representation categories that may be provided for any family of parts.
These integrated EXPRESS information models contain provisions that permit a supplier library to reference external files. For each integrated EXPRESS information model, ISO 13584-24:2003 specifies which formats are allowed for these external files. Other external file formats are defined in the view exchange protocol series of parts of ISO 13584.