1. Carzaniga, A., Rosenblum, D.S., Wolf, A.L.: Design and evaluation of a wide-area event notification service. ACM Transactions on Computer Systems 19, 332–383 (2001)
2. Lisha, G., Junzhou, L.: Performance analysis of a P2P-based VoIP software, p. 11. Guadelope, French Southern Territories (2006)
3. Urrutia-Valdes, C., Mukhopadhyay, A., El-Sayed, M.: Presence and availability with IMS: Applications architecture, traffic analysis, and capacity impacts. Bell Labs Technical Journal 10, 101–107 (2006)
4. Vishal, S.K., Hening, S.H.: Presence traffic optimization techniques, http://Sdev.voip.co.uk/~theo/misc/presence-traffic-optimization-techniques.pdf
5. Alam, M.T., WuCost, Z.D.: Cost Analysis of the IMS Presence Service. In: 1st Australian Confrence on Wireless Broadband and Ultra Wideband Communication, AusWireless 2006, Sydney, March 13-16 (2006)