@inproceedings{SIGMOD-1979-Fagin,
	author        = "Ronald Fagin",
	booktitle     = "{Proceedings of the Ninth ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD79/P153.PDF",
	doi           = "10.1145/582095.582120",
	isbn          = "0-89791-001-X",
	pages         = "153--160",
	publisher     = "{ACM}",
	title         = "{Normal Forms and Relational Database Operators}",
	year          = 1979,
}