@inproceedings{KR-1989-Lehmann,
	author        = "Daniel J. Lehmann",
	booktitle     = "{Proceedings of the First International Conference on Principles of Knowledge Representation and Reasoning}",
	isbn          = "1-55860-032-9",
	pages         = "212--222",
	publisher     = "{Morgan Kaufmann}",
	title         = "{What Does a Conditional Knowledge Base Entail?}",
	year          = 1989,
}