@inproceedings{SIGMOD-1977-FurtadoK,
	author        = "Antonio L. Furtado and Larry Kerschberg",
	booktitle     = "{Proceedings of the Seventh ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD77/P001.PDF",
	doi           = "10.1145/509404.509406",
	pages         = "1--8",
	publisher     = "{ACM}",
	title         = "{An Algebra of Quotient Relations}",
	year          = 1977,
}