@inproceedings{SIGMOD-1975-SchmidS,
	author        = "Hans Albrecht Schmid and J. Richard Swenson",
	booktitle     = "{Proceedings of the Fifth ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD75/P211.PDF",
	doi           = "10.1145/500080.500110",
	pages         = "211--223",
	publisher     = "{ACM}",
	title         = "{On the Semantics of the Relational Data Model}",
	year          = 1975,
}