@article{Donner1994,
	title = {Cluster randomization trials in epidemiology: theory and application},
	author = {Allan Donner and Neil Klar},
	journal = {Journal of Statistical Planning and Inference},
	month = {Nov},
	number = {1-2},
	pages = {37--56},
	url = {http://www.sciencedirect.com/science/article/B6V0M-45FCH4D-4/1/30c7aa163259d7669e29e52c0ca78315},
	volume = {42},
	year = {1994},
	biburl = {http://www.bibsonomy.org/bibtex/2b81f70cb4dd4d6892204be2d9e26b652/smicha},
	keywords = {Cluster randomization }
}