@article{1093883181,
author = {Hughes, G. E.},
title = {Equivalence relations and ${\rm S}5$.},
journal = {Notre Dame J. Formal Logic},
volume = {21},
number = {1},
year = {1980},
pages = { 577-584},
language = {en},
url = {http://dml.mathdoc.fr/item/1093883181}
}
Hughes, G. E. Equivalence relations and ${\rm S}5$.. Notre Dame J. Formal Logic, Tome 21 (1980) no. 1, pp. 577-584. http://gdmltest.u-ga.fr/item/1093883181/