@inproceedings{SIGIR-1973-Mitchell,
	author        = "Patrick C. Mitchell",
	booktitle     = "{Proceedings of the ACM SIGIR meeting on Programming Languages and Information Retrieval}",
	pages         = "177--179",
	publisher     = "{ACM}",
	title         = "{A Note About the Proximity Operators in Information Retieval}",
	year          = 1973,
}