@book{15203,
	author = {Ahlbom, Anders.},
	title = {Biostatistics for epidemiologists /},
	publisher = {Lewis Publishers,},
	year = {c1993.},
	address = {Boca Raton :},
	url = {http://www.loc.gov/catdir/enhancements/fy0744/93006595-d.html}
}