@book{208,
	author = {Lipschutz, Seymour. and  Lipson, Marc Lars.},
	title = {Theory and problems discrete mathematics /},
	publisher = {Tata McGraw-Hill,},
	year = {c2008.},
	series = {Schaum's outline of Math},
	address = {New Delhi:},
	edition = {7th ed.},
	note = {Includes index.}
}