A petri net based XML firewall security model for web services invocation. - Mihir M. Ayachit; Haiping Xu (Communication, Network, and Information Security, 2006)

Formal modelling and analysis of XML firewall for service-oriented systems. - Haiping Xu; Mihir M. Ayachit; Abhinay Reddyreddy (Int. J. Secur. Networks, 2008)