@inproceedings{ILPS-1994-Turner,
	author        = "Hudson Turner",
	booktitle     = "{Proceedings of the International Symposium on Logic Programming}",
	isbn          = "0-262-52191-1",
	pages         = "61--75",
	publisher     = "{MIT Press}",
	title         = "{Signed Logic Programs}",
	year          = 1994,
}