@book{213956,
	author = {Twisk, Jos W. R., and ebrary, Inc.},
	title = {Applied longitudinal data analysis for epidemiology},
	publisher = {Cambridge University Press,},
	year = {2003.},
	address = {Cambridge, UK ;},
	url = {http://site.ebrary.com/lib/strathmore/Doc?id=10070002}
}