@book{1591,
	author = {Maindonald, J. H. and Braun, John,},
	title = {Data analysis and graphics using R :},
	publisher = {Cambridge University Press,},
	year = {2003.},
	series = {Cambridge series in statistical and probabilistic mathematics},
	address = {Cambridge, UK ;},
	url = {http://www.loc.gov/catdir/description/cam031/2002031560.html}
}