@book{239639,
	author = {Eldridge, Sandra. and Kerry, Sally M. and ebrary, Inc.},
	title = {A practical guide to cluster randomised trials in health services research},
	publisher = {John Wiley & Sons,},
	year = {2012.},
	series = {Statistics in practice},
	address = {Chichester, West Sussex :},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10524069}
}