@inproceedings{KR-1991-MarekST,
	author        = "V. Wiktor Marek and Grigori F. Shvarts and Miroslaw Truszczynski",
	booktitle     = "{Proceedings of the Second International Conference on Principles of Knowledge Representation and Reasoning}",
	isbn          = "1-55860-165-1",
	pages         = "395--404",
	publisher     = "{Morgan Kaufmann}",
	title         = "{Modal Nonmonotonic Logics: Ranges, Characterization, Computation}",
	year          = 1991,
}