@inproceedings{ML-1988-Helft,
	author        = "Nicolas Helft",
	booktitle     = "{Proceedings of the Fifth International Workshop on Machine Learning}",
	isbn          = "0-934613-64-8",
	pages         = "395--401",
	publisher     = "{Morgan Kaufmann}",
	title         = "{Learning Systems of First-Order Rules}",
	year          = 1988,
}