@article{1093893352,
author = {Cresswell, M. J.},
title = {Some proofs of relative completeness in modal logic.},
journal = {Notre Dame J. Formal Logic},
volume = {9},
number = {1},
year = {1968},
pages = { 62-66},
language = {en},
url = {http://dml.mathdoc.fr/item/1093893352}
}
Cresswell, M. J. Some proofs of relative completeness in modal logic.. Notre Dame J. Formal Logic, Tome 9 (1968) no. 1, pp. 62-66. http://gdmltest.u-ga.fr/item/1093893352/