@inproceedings{CLP-1990-PowerS90,
	author        = "A. John Power and Leon Sterling",
	booktitle     = "{Proceedings of the Seventh International Conference on Logic Programming}",
	isbn          = "0-262-73090-1",
	pages         = "390--404",
	publisher     = "{MIT Press}",
	title         = "{A Notion of Map between Logic Programs}",
	year          = 1990,
}