@article{2220,
author = {Bergmann, Gustav},
title = {Multiplicative closures},
journal = {Portugaliae mathematica},
volume = {11},
year = {1952},
pages = {169-172},
zbl = {0048.02203},
mrnumber = {0052391},
language = {en},
url = {http://dml.mathdoc.fr/item/2220}
}
Bergmann, Gustav. Multiplicative closures. Portugaliae mathematica, Tome 11 (1952) pp. 169-172. http://gdmltest.u-ga.fr/item/2220/