@article{1093957504, author = {Massey, Gerald J.}, title = {Note on Copi's system.}, journal = {Notre Dame J. Formal Logic}, volume = {4}, number = {1}, year = {1963}, pages = { 140-141}, language = {en}, url = {http://dml.mathdoc.fr/item/1093957504} }
Massey, Gerald J. Note on Copi's system.. Notre Dame J. Formal Logic, Tome 4 (1963) no. 1, pp. 140-141. http://gdmltest.u-ga.fr/item/1093957504/