@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/