@inproceedings{NACLP-1989-Przymusinski,
	author        = "Teodor C. Przymusinski",
	booktitle     = "{Proceedings of the North American Conference on Logic Programming, 2 Volumes}",
	isbn          = "0-262-62064-2",
	pages         = "0",
	publisher     = "{MIT Press}",
	title         = "{On Constructive Negation in Logic Programming}",
	year          = 1989,
}