@article{1093894298,
author = {Zeman, J. Jay},
title = {A study of some systems in the neighborhood of ${\rm S}4.4$.},
journal = {Notre Dame J. Formal Logic},
volume = {12},
number = {1},
year = {1971},
pages = { 341-357},
language = {en},
url = {http://dml.mathdoc.fr/item/1093894298}
}
Zeman, J. Jay. A study of some systems in the neighborhood of ${\rm S}4.4$.. Notre Dame J. Formal Logic, Tome 12 (1971) no. 1, pp. 341-357. http://gdmltest.u-ga.fr/item/1093894298/