1. ETSI TS 183 043 (2006). Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN). IMS-based PSTN/ISDN Emulation Stage 3 specification. European Telecommunications Standards Institute, May.
2. ETSI TS 181 002 (2006). Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN). Multimedia Telephony with PSTN/ISDN Simulation Services. European Telecommunications Standards Institute, May.
3. 3rd Generation Partnership Project (2005). IP Multimedia Subsystem (IMS). Stage 2, Release 7, TS 23.228 V7.2.0, December.
4. ETSI EG 201 973-2 (2003). Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN). Access and Terminals; PSTN; Support of Legacy Terminals by Broadband IP Networks and Equipment; Analog PSTN Terminal. European Telecommunications Standards Institute, March.
5. Joseph, J.-P. (2008). IMS network signaling peering: challenges and proposal. Bell Labs Technical Journal, 12(4), 33–48.