@article{GDZPPN002219298,
title = {Symmetric Semigroups of Integers Generated by 4 Elements.},
journal = {Manuscripta mathematica},
volume = {17},
year = {1975},
pages = {205-220},
zbl = {0317.10061},
url = {http://dml.mathdoc.fr/item/GDZPPN002219298}
}
Bresinsky, H. Symmetric Semigroups of Integers Generated by 4 Elements.. Manuscripta mathematica, Tome 17 (1975) pp. 205-220. http://gdmltest.u-ga.fr/item/GDZPPN002219298/