@article{1183354818, author = {Emch, Arnold F.}, title = {Deducibility with Respect to Necessary and Impossible Propositions}, journal = {J. Symbolic Logic}, volume = {2}, number = {2}, year = {1937}, pages = { 78-81}, language = {en}, url = {http://dml.mathdoc.fr/item/1183354818} }
Emch, Arnold F. Deducibility with Respect to Necessary and Impossible Propositions. J. Symbolic Logic, Tome 2 (1937) no. 2, pp. 78-81. http://gdmltest.u-ga.fr/item/1183354818/