@book{37322,
	author = {Koepsell, Thomas D. and Weiss, Noel S.,},
	title = {Epidemiologic methods},
	publisher = {Oxford University Press,},
	year = {2003.},
	address = {New York ;},
	url = {http://dx.doi.org/10.1093/acprof:oso/9780195150780.001.0001}
}