@article{1261147294,
author = {M. SMULLYAN, Raymond},
title = {Elementary formal systems},
journal = {J. Math. Soc. Japan},
volume = {13},
number = {4},
year = {1961},
pages = { 38-44},
language = {en},
url = {http://dml.mathdoc.fr/item/1261147294}
}
M. SMULLYAN, Raymond. Elementary formal systems. J. Math. Soc. Japan, Tome 13 (1961) no. 4, pp. 38-44. http://gdmltest.u-ga.fr/item/1261147294/