@article{1183738761,
author = {Lewis, Harry R. and Goldfarb, Warren D.},
title = {The Decision Problem for Formulas with a Small Number of Atomic Subformulas},
journal = {J. Symbolic Logic},
volume = {38},
number = {1},
year = {1973},
pages = { 471-480},
language = {en},
url = {http://dml.mathdoc.fr/item/1183738761}
}
Lewis, Harry R.; Goldfarb, Warren D. The Decision Problem for Formulas with a Small Number of Atomic Subformulas. J. Symbolic Logic, Tome 38 (1973) no. 1, pp. 471-480. http://gdmltest.u-ga.fr/item/1183738761/