@inproceedings{KR-1989-KautzS,
	author        = "Henry A. Kautz and Bart Selman",
	booktitle     = "{Proceedings of the First International Conference on Principles of Knowledge Representation and Reasoning}",
	isbn          = "1-55860-032-9",
	pages         = "189--197",
	publisher     = "{Morgan Kaufmann}",
	title         = "{Hard Problems for Simple Default Logics}",
	year          = 1989,
}