@book{218145,
	author = {Rosen, Kenneth H.},
	title = {Discrete Mathematics and its Applications /},
	publisher = {McGraw-Hill,},
	year = {c2012.},
	address = {New York :},
	edition = {7th ed.},
	url = {http://www.loc.gov/catdir/enhancements/fy1110/2011011060-b.html}
}