@article{1093887736,
author = {Gilbert, Michael A.},
title = {A heuristic procedure for natural deduction derivations using reductio ad absurdum.},
journal = {Notre Dame J. Formal Logic},
volume = {17},
number = {1},
year = {1976},
pages = { 638-639},
language = {en},
url = {http://dml.mathdoc.fr/item/1093887736}
}
Gilbert, Michael A. A heuristic procedure for natural deduction derivations using reductio ad absurdum.. Notre Dame J. Formal Logic, Tome 17 (1976) no. 1, pp. 638-639. http://gdmltest.u-ga.fr/item/1093887736/