@inproceedings{NACLP-1989-Helm,
	author        = "A. Richard Helm",
	booktitle     = "{Proceedings of the North American Conference on Logic Programming, 2 Volumes}",
	isbn          = "0-262-62064-2",
	pages         = "945--962",
	publisher     = "{MIT Press}",
	title         = "{On the Dedection and Elimination of Redundant Derivations during Bottom-up Execution}",
	year          = 1989,
}