ETSI TS 129 061 Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Packet Domain; Interworking between the Public Land Mobile Network (PLMN) supporting Packet Based Services and Packet Data Networks (PDN) (3G TS 29.061 version 3.3.0 Release 1999)

standard by European Telecommunications Standards Institute, 03/01/2000