@inproceedings{ILPS-1997-GrecoS,
	author        = "Sergio Greco and Domenico Saccà",
	booktitle     = "{Proceedings of the International Symposium on Logic Programming}",
	isbn          = "0-262-63180-6",
	pages         = "181--195",
	publisher     = "{MIT Press}",
	title         = "{NP Optimization Problems in Datalog}",
	year          = 1997,
}