@inproceedings{SIGMOD-1975-WelchG,
	author        = "James W. Welch and J. Wesley Graham",
	booktitle     = "{Proceedings of the Fifth ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD75/P092.PDF",
	doi           = "10.1145/500080.500093",
	pages         = "92--98",
	publisher     = "{ACM}",
	title         = "{Information Retrieval in Files Described Using Sets}",
	year          = 1975,
}