APA (7th ed.) Citation

Safari Tech Books Online, Hersent, O. A., & Gurle, D. C. (1999). IP Telephony: Packet Based Multimedia Communications Systems (1st edition.). Addison Wesley Professional.

Chicago Style (17th ed.) Citation

Safari Tech Books Online, Olivier Author Hersent, and David Contributor Gurle. IP Telephony: Packet Based Multimedia Communications Systems. 1st edition. [Place of publication not identified]: Addison Wesley Professional, 1999.

MLA (9th ed.) Citation

Safari Tech Books Online, et al. IP Telephony: Packet Based Multimedia Communications Systems. 1st edition. Addison Wesley Professional, 1999.