@inproceedings{ICALP-1989-TuckerZ,
	author        = "J. V. Tucker and Jeffery I. Zucker",
	booktitle     = "{Proceedings of the 16th International Colloquium on Automata, Languages and Programming}",
	doi           = "10.1007/BFb0035796",
	isbn          = "3-540-51371-X",
	pages         = "745--760",
	publisher     = "{Springer-Verlag}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{Horn Programs and Semicomputable Relations on Abstract Structures}",
	volume        = 372,
	year          = 1989,
}