@book{42709,
	author = {Biggs, Norman L.},
	title = {Discrete mathematics},
	publisher = {Oxford University Prees},
	year = {2002},
	address = {Estados Unidos de América :},
	edition = {2},
	note = {Incluye índice},
	url = {http://biblioteca.unac.edu.co/portadas/54836.jpg}
}