@book{40193,
	author = {Maindonald, J. H. and Braun, John,},
	title = {Data analysis and graphics using R :},
	publisher = {Cambridge University Press,},
	year = {2007.},
	series = {Cambridge series in statistical and probabilistic mathematics},
	address = {Cambridge ;},
	edition = {2nd ed.},
	note = {Previous ed.: 2003.},
	url = {http://www.loc.gov/catdir/enhancements/fy0726/2007274828-d.html}
}