@inproceedings{JICSLP-1992-AlferesP,
	author        = "José Júlio Alferes and Luís Moniz Pereira",
	booktitle     = "{Proceedings of the Joint International Ninth Conference and Symposium on Logic Programming}",
	isbn          = "0-262-51064-2",
	pages         = "574--588",
	publisher     = "{MIT Press}",
	title         = "{On Logic Program Semantics with Two Kinds of Negation}",
	year          = 1992,
}