@article{GDZPPN002043505,
title = {On the existence of an empty set in set-theoretical methods.},
journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
volume = {10},
year = {1966},
pages = {123-126},
zbl = {0189.28604},
url = {http://dml.mathdoc.fr/item/GDZPPN002043505}
}
Abian, A.; LaMacchia, S. On the existence of an empty set in set-theoretical methods.. Archiv für mathematische Logik und Grundlagenforschung, Tome 10 (1966) pp. 123-126. http://gdmltest.u-ga.fr/item/GDZPPN002043505/