@article{1094068849, author = {Thomas, Ivo}, title = {A theorem on ${\rm S}4.2$ and ${\rm S}4.4$.}, journal = {Notre Dame J. Formal Logic}, volume = {8}, number = {3}, year = {1967}, pages = { 335-336}, language = {en}, url = {http://dml.mathdoc.fr/item/1094068849} }
Thomas, Ivo. A theorem on ${\rm S}4.2$ and ${\rm S}4.4$.. Notre Dame J. Formal Logic, Tome 8 (1967) no. 3, pp. 335-336. http://gdmltest.u-ga.fr/item/1094068849/