@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/