@article{1183736253,
author = {Hanson, William H.},
title = {Review: Frederic B. Fitch, Natural Deduction Rules for Obligation},
journal = {J. Symbolic Logic},
volume = {33},
number = {1},
year = {1968},
pages = { 136-137},
language = {en},
url = {http://dml.mathdoc.fr/item/1183736253}
}
Hanson, William H. Review: Frederic B. Fitch, Natural Deduction Rules for Obligation. J. Symbolic Logic, Tome 33 (1968) no. 1, pp. 136-137. http://gdmltest.u-ga.fr/item/1183736253/