@book{3828,
	author = {Balakrishnan, V. K.},
	title = {Schaum's outline of theory and problems of combinatorics},
	publisher = {McGraw Hill},
	year = {1995},
	address = {New York},
	url = {https://www.libgen.is/book/index.php?md5=EBA93E2256C34AB10144B06BFAC9C3DA}
}