@inproceedings{POPL-1981-HalpernM,
	author        = "Joseph Y. Halpern and Albert R. Meyer",
	booktitle     = "{Conference Record of the Eighth Annual Symposium on Principles of Programming Languages}",
	doi           = "10.1145/567532.567548",
	editor        = "John White and Richard J. Lipton and Patricia C. Goldberg",
	isbn          = "0-89791-029-X",
	pages         = "139--148",
	publisher     = "{ACM Press}",
	title         = "{Axiomatic Definitions of Programming Languages, II}",
	year          = 1981,
}