@inproceedings{NACLP-1989-WilsonB,
	author        = "Molly Wilson and Alan Borning",
	booktitle     = "{Proceedings of the North American Conference on Logic Programming, 2 Volumes}",
	isbn          = "0-262-62064-2",
	pages         = "3--19",
	publisher     = "{MIT Press}",
	title         = "{Extending Hierarchical Constraint Logic Programming: Nonmonotonicity and Inter-Hierarchy Comparison}",
	year          = 1989,
}