@book{6445,
	author = {Porter, Thomas, and Gough, Michael,},
	title = {How to Cheat at Voip Security /},
	publisher = {Syngress,},
	year = {c2007.},
	address = {Rockland, MA :},
	note = {Includes index.},
	url = {http://www.loc.gov/catdir/enhancements/fy0742/2007298838-d.html}
}