4J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler. SIP:Session Initiation Protocol (RFC3261) [S]. IETF Network Working Group, June 2002.
5J. Rosenberg, H. Schulzrinne. An Offer/Answer Model with the Session Description Protocol (RFC3264)[S I. 2002.
6Schulzrinne H. , Casner S. , Frederick R. , and V. Jacobson. "RTP : A Transport Protocol for Real - Time Applications", STD 64, RFC 3550 [S]. July 2003.