@ARTICLE(       UV88b,
	AUTHOR = "Ullman, Jeffrey D. and Van Gelder, Allen",
	TITLE = "Efficient tests for top-down termination of logical rules",
	JOURNAL = "Journal of the ACM",
	VOLUME = "35", NUMBER = "2",
	PAGES = "345--373",
	URL = "http://portal.acm.org/citation.cfm?id=42285",
	NOTE = "(Preprint available from second author)",
	YEAR = "1988"   )