ETSI EN 301 349 Digital cellular telecommunications system (Phase 2+) (GSM); General Packet Radio Service (GPRS); Mobile Station (MS) - Base Station System (BSS) interface; Radio Link Control / Medium Access Control (RLC/MAC) protocol (GSM 04.60 version 6.3.1 Release 1997)

standard by European Telecommunications Standards Institute, 06/01/1999