@book{12188,
	author = {Hayes, Richard J., and Moulton, Lawrence H.},
	title = {Cluster randomised trials},
	publisher = {CRC Press,},
	year = {c2009.},
	series = {Interdisciplinary statistics series},
	address = {Boca Raton :},
	note = {"A Chapman & Hall book."},
	url = {http://marc.crcnetbase.com/isbn/9781584888178}
}