@inproceedings{SIGMOD-1977-PaoliniP,
	author        = "Paolo Paolini and Giuseppe Pelagatti",
	booktitle     = "{Proceedings of the Seventh ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD77/P040.PDF",
	doi           = "10.1145/509404.509413",
	pages         = "40--46",
	publisher     = "{ACM}",
	title         = "{Formal Definition of Mappings in a Data Base}",
	year          = 1977,
}