@book{227814,
	author = {Johnston, Alan B. and Piscitello, David M. and ebrary, Inc.},
	title = {Understanding Voice over IP security},
	publisher = {Artech House,},
	year = {c2006.},
	series = {Artech House telecommunications library},
	address = {Boston, MA :},
	url = {http://site.ebrary.com/lib/strathmore/Doc?id=10160961}
}