@book{21887,
	author = {BURKARD, Reiner E. and DERIGS, Ulrich},
	title = {Assigniment and matching problems :},
	year = {1980.},
	series = {Lecture Notes in Economics and Mathematical Systems ;},
	address = {Berlin,},
	url = {http://koha.tu.koszalin.pl/cgi-bin/koha/opac-detail.pl?biblionumber=21887}
}