@book{7424,
	author = {Murray, David M.},
	title = {Design and analysis of group-randomized trials /},
	publisher = {Oxford University Press,},
	year = {1998.},
	series = {Monographs in epidemiology and biostatistics ;},
	address = {New York :},
	url = {http://www.loc.gov/catdir/enhancements/fy0605/97020411-d.html}
}