@article{1093891709,
author = {Pledger, K. E.},
title = {Some extensions of $S3$.},
journal = {Notre Dame J. Formal Logic},
volume = {16},
number = {1},
year = {1975},
pages = { 271-272},
language = {en},
url = {http://dml.mathdoc.fr/item/1093891709}
}
Pledger, K. E. Some extensions of $S3$.. Notre Dame J. Formal Logic, Tome 16 (1975) no. 1, pp. 271-272. http://gdmltest.u-ga.fr/item/1093891709/