ETSI TS 132 015 Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Telecommunication Management; Charging and billing; GSM call and event data for the Packet Switched (PS) domain (3G TS 32.015 version 3.2.0 Release 1999)

standard by European Telecommunications Standards Institute, 07/01/2000