@article{GDZPPN002046113,
title = {Unramified forcing preserving the law of double negation.},
journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
volume = {26},
year = {1987},
pages = {177-180},
zbl = {0645.03049},
url = {http://dml.mathdoc.fr/item/GDZPPN002046113}
}
Abian, A.; Keremedis, K. Unramified forcing preserving the law of double negation.. Archiv für mathematische Logik und Grundlagenforschung, Tome 26 (1987) pp. 177-180. http://gdmltest.u-ga.fr/item/GDZPPN002046113/