ETSI TS 122 001 English Printed Edition English PDF Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Principles of circuit telecommunication services supported by a Public Land Mobile Network (PLMN) (3G TS 22.001 version 3.2.0 Release 1999)

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