@inproceedings{SIGFIDET-1971-DateH,
	author        = "C. J. Date and P. Hopewell",
	booktitle     = "{Proceedings of the Second ACM-SIGFIDET Workshop on Data Description, Access and Control}",
	cdrom         = "SIGFIDET71/P117.pdf",
	pages         = "117--138",
	publisher     = "{ACM}",
	title         = "{File Definition and Logical Data Independence}",
	year          = 1971,
}