Services and technical considerations for the wireless IP multimedia subsystem. - John G. Adamek; Eric H. Henrikson; Harold A. Lassers; Anne Y. Lee; Ronald B. Martin (Bell Labs Tech. J., 2002)

Private Header (P-Header) Extensions to the Session Initiation Protocol (SIP) for the 3rd-Generation Partnership Project (3GPP). - Miguel A. Garcia-Martin; Eric H. Henrikson; Duncan Mills (RFC, 2003)