@article{1117559008,
author = {Henkin, Leon},
title = {Extending Boolean operations.},
journal = {Pacific J. Math.},
volume = {35},
number = {3},
year = {1970},
pages = { 723-752},
language = {en},
url = {http://dml.mathdoc.fr/item/1117559008}
}
Henkin, Leon. Extending Boolean operations.. Pacific J. Math., Tome 35 (1970) no. 3, pp. 723-752. http://gdmltest.u-ga.fr/item/1117559008/