@article{1093894010,
author = {Winnie, John A.},
title = {The completeness of Copi's system of natural deduction.},
journal = {Notre Dame J. Formal Logic},
volume = {11},
number = {1},
year = {1970},
pages = { 379-382},
language = {en},
url = {http://dml.mathdoc.fr/item/1093894010}
}
Winnie, John A. The completeness of Copi's system of natural deduction.. Notre Dame J. Formal Logic, Tome 11 (1970) no. 1, pp. 379-382. http://gdmltest.u-ga.fr/item/1093894010/