@article{1154698578,
author = {Medeiros, Maria da Paz N.},
title = {A new S4 classical modal logic in natural deduction},
journal = {J. Symbolic Logic},
volume = {71},
number = {1},
year = {2006},
pages = { 799-809},
language = {en},
url = {http://dml.mathdoc.fr/item/1154698578}
}
Medeiros, Maria da Paz N. A new S4 classical modal logic in natural deduction. J. Symbolic Logic, Tome 71 (2006) no. 1, pp. 799-809. http://gdmltest.u-ga.fr/item/1154698578/