Canavan, J.E. (2001). Fundamentals of Network Security. Retrieved June 28, 2014, from http://f3.tiera.ru/other/DVD-005/Canavan_J.E._Fundamentals_of_network_security_(2001)(en)(218s).pdf
Cheesley, R. (2010, July 29). White Paper: Network Security for Small and Medium Sized
Businesses. Retrieved June 28, 2014, from http://www.viryatechnologies.com/what-we-are-up-to/white-papers/white-paper-network-security-for-small-and-medium-sized-businesses.html
Stewart, J.M. (2013). Network security, firewalls, and VPNs (2nd ed.). Burlington, MA: Jones & Bartlett Learning.