Detecting More SIP Attacks on VoIP Services by Combining Rule Matching and State Transition Models. - Dongwon Seo; Heejo Lee; Ejovi Nuwere (SEC, 2008)

SIPAD: SIP-VoIP Anomaly Detection using a Stateful Rule Tree. - Dongwon Seo; Heejo Lee; Ejovi Nuwere (Comput. Commun., 2013)