1. ETSI: ETSI TS 100 522 Digital cellular telecommunications system (Phase 2+): Network architecture (GSM 03.02 version 7.1.0 Release 1998): 2000
2. ITU-T: Recommendations Q.711–Q.714 Specifications of Signalling System No. 7 — Signalling connection control part: 1996
3. ETSI: ETSI TS 100 940 Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 specification (3GPP TS 04.08 version 7.17.0 Release 1998): 2002
4. ETSI: ETSI TS 129 002 Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Mobile Application Part (MAP) specification (2GPP TS 29.002 version 4.50 Release 4): 2001
5. ITU-T: Recommendations Q.761–Q.764 Signalling System No. 7 — ISDN user part signalling procedures: 1999