@inproceedings{SIGMOD-1977-Schmidt,
	author        = "Joachim W. Schmidt",
	booktitle     = "{Proceedings of the Seventh ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD77/P009.PDF",
	doi           = "10.1145/509404.509407",
	pages         = "9",
	publisher     = "{ACM}",
	title         = "{Some High-level Language Constructs for Data of Type Relation}",
	year          = 1977,
}