3HAMED H, AL-SHAER E. Modeling and Verification of IP- Sec and VPN Security Policies [ C ]//13th IEEE International Conference on Network Protocols, ICNP 2005. Boston: [ s. n. ] ,2005:259 - 268.
4BERGER T. Analysis of Current VPN Technologies[ C]// First Inernational Conference on Auailability, Reliability and Security, ARES 2006. Vienna: [s. n. ] ,2006:108 - 115.