@article{1093891316, author = {Blum, Alex}, title = {A note on natural deduction.}, journal = {Notre Dame J. Formal Logic}, volume = {15}, number = {1}, year = {1974}, pages = { 349-350}, language = {en}, url = {http://dml.mathdoc.fr/item/1093891316} }
Blum, Alex. A note on natural deduction.. Notre Dame J. Formal Logic, Tome 15 (1974) no. 1, pp. 349-350. http://gdmltest.u-ga.fr/item/1093891316/