@article{1183730734, author = {Fitch, Frederic B.}, title = {A Further Consistent Extension of Basic Logic}, journal = {J. Symbolic Logic}, volume = {14}, number = {4}, year = {1950}, pages = { 209-218}, language = {en}, url = {http://dml.mathdoc.fr/item/1183730734} }
Fitch, Frederic B. A Further Consistent Extension of Basic Logic. J. Symbolic Logic, Tome 14 (1950) no. 4, pp. 209-218. http://gdmltest.u-ga.fr/item/1183730734/