ETSI TS 101 343 Digital cellular telecommunications system (Phase 2+) (GSM); General Packet Radio Service (GPRS); Base Station System (BSS) - Serving GPRS Support Node (SGSN); BSS GPRS Protocol (BSSGP) (3GPP TS 08.18 version 8.5.1 Release 1999)

standard by European Telecommunications Standards Institute, 01/01/2001