@article{1077490201,
author = {Birkhoff, Garrett},
title = {Rings of sets},
journal = {Duke Math. J.},
volume = {3},
number = {1},
year = {1937},
pages = { 443-454},
language = {en},
url = {http://dml.mathdoc.fr/item/1077490201}
}
Birkhoff, Garrett. Rings of sets. Duke Math. J., Tome 3 (1937) no. 1, pp. 443-454. http://gdmltest.u-ga.fr/item/1077490201/