@inproceedings{SIGMOD-1990-Saraiya,
	author        = "Yatin P. Saraiya",
	booktitle     = "{Proceedings of the 20th ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD90/P064.PDF",
	doi           = "10.1145/93597.93622",
	pages         = "64--73",
	title         = "{Hard Problems for Simple Logic Programs}",
	year          = 1990,
}