@inproceedings{VLDB-1980-Date,
	author        = "C. J. Date",
	booktitle     = "{Proceedings of the Sixth International Conference on Very Large Data Bases}",
	cdrom         = "VLDB80/P015.PDF",
	pages         = "15--32",
	publisher     = "{IEEE Computer Society}",
	title         = "{An Introduction to the Unified Database Language (UDL)}",
	year          = 1980,
}