@inproceedings{SIGFIDET-1972-HawryszkiewyczD,
	author        = "Igor Hawryszkiewycz and Jack B. Dennis",
	booktitle     = "{Proceedings of the Third ACM-SIGFIDET Workshop on Data Description, Access and Control}",
	cdrom         = "SIGFIDET72/P323.pdf",
	pages         = "323--348",
	publisher     = "{ACM}",
	title         = "{An Approach to Proving the Correctness of Data Base Operations}",
	year          = 1972,
}