@article{03777451,
title = {Minimal modal systems in which Heyting and classical logic can be embedded.},
journal = {Publications de l'Institut Math\'ematique. Nouvelle S\'erie},
volume = {29(43)},
year = {1981},
pages = {41-52},
zbl = {0494.03008},
language = {en},
url = {http://dml.mathdoc.fr/item/03777451}
}
Dosen, Kosta. Minimal modal systems in which Heyting and classical logic can be embedded.. Publications de l'Institut Mathématique. Nouvelle Série, Tome 29(43) (1981) pp. 41-52. http://gdmltest.u-ga.fr/item/03777451/