@article{1093887424,
author = {Routley, R. and Montgomery, Hugh Alexander},
title = {Algebraic semantics for $S2^0$ and necessitated extensions.},
journal = {Notre Dame J. Formal Logic},
volume = {17},
number = {1},
year = {1976},
pages = { 44-58},
language = {en},
url = {http://dml.mathdoc.fr/item/1093887424}
}
Routley, R.; Montgomery, Hugh Alexander. Algebraic semantics for $S2^0$ and necessitated extensions.. Notre Dame J. Formal Logic, Tome 17 (1976) no. 1, pp. 44-58. http://gdmltest.u-ga.fr/item/1093887424/