@article{GDZPPN001260774,
title = {Arithmetical semigroups defined by congruences.},
journal = {Semigroup forum},
volume = {43},
year = {1991},
pages = {59-62},
zbl = {0734.20027},
url = {http://dml.mathdoc.fr/item/GDZPPN001260774}
}
Halter-Koch, F. Arithmetical semigroups defined by congruences.. Semigroup forum, Tome 43 (1991) pp. 59-62. http://gdmltest.u-ga.fr/item/GDZPPN001260774/