@article{1093893940,
author = {Gregg, John R.},
title = {Axiomatic quasi-natural deduction.},
journal = {Notre Dame J. Formal Logic},
volume = {11},
number = {1},
year = {1970},
pages = { 221-228},
language = {en},
url = {http://dml.mathdoc.fr/item/1093893940}
}
Gregg, John R. Axiomatic quasi-natural deduction.. Notre Dame J. Formal Logic, Tome 11 (1970) no. 1, pp. 221-228. http://gdmltest.u-ga.fr/item/1093893940/