@inproceedings{VLDB-1981-BorgidaW,
	author        = "Alexander Borgida and Harry K. T. Wong",
	booktitle     = "{Proceedings of the Seventh International Conference on Very Large Data Bases}",
	cdrom         = "VLDB81/P260.PDF",
	pages         = "260--271",
	publisher     = "{IEEE Computer Society}",
	title         = "{Data Models and Data Manipulation Languages: Complementary Semantics and Proof Theory}",
	year          = 1981,
}