@article{1093882942,
author = {Englebretsen, George},
title = {On propositional form.},
journal = {Notre Dame J. Formal Logic},
volume = {21},
number = {1},
year = {1980},
pages = { 101-110},
language = {en},
url = {http://dml.mathdoc.fr/item/1093882942}
}
Englebretsen, George. On propositional form.. Notre Dame J. Formal Logic, Tome 21 (1980) no. 1, pp. 101-110. http://gdmltest.u-ga.fr/item/1093882942/