@book{72514,
	author = {Campbell, Michael J., and Walters, Stephen John.},
	title = {Medical statistics :},
	publisher = {Wiley,},
	year = {2007.},
	address = {Chichester, England ;},
	edition = {4th ed.},
	url = {http://www.loc.gov/catdir/toc/ecip0715/2007015897.html}
}