@INPROCEEDINGS{spans,
	AUTHOR = "E. W. Stark",
	TITLE = "Compositional Relational Semantics for Indeterminate
			Dataflow Networks",
	BOOKTITLE = "Proceedings of Summer Conference on Category Theory
			and Computer Science",
	PUBLISHER = "Springer-Verlag",
	SERIES = "Lecture Notes in Computer Science",
	CITY = "Manchester, U.K.",
	YEAR = "1989",
	MONTH = SEP,
	VOLUME = 389,
	PAGES = "52--74"
}