@inproceedings{SLP-1987-Wallace87,
	author        = "Mark Wallace",
	booktitle     = "{Proceedings of the Fourth Symposium on Logic Programming}",
	isbn          = "0-8186-0799-8",
	pages         = "253--263",
	publisher     = "{IEEE-CS}",
	title         = "{Negation by Constraints: A Sound and Efficient Implementation of Negation in Deductive Databases}",
	year          = 1987,
}