Fred S. Roberts. Tolerance geometry. Notre Dame Journal of Formal Logic, 14(1):68-76, 1973. [doi]
@article{Roberts73-0,
title = {Tolerance geometry},
author = {Fred S. Roberts},
year = {1973},
doi = {10.1305/ndjfl/1093890809},
url = {http://dx.doi.org/10.1305/ndjfl/1093890809},
researchr = {https://researchr.org/publication/Roberts73-0},
cites = {0},
citedby = {0},
journal = {Notre Dame Journal of Formal Logic},
volume = {14},
number = {1},
pages = {68-76},
}