@article{GDZPPN001252941, title = {On groups of units in a special class of monoids.}, journal = {Semigroup forum}, volume = {16}, year = {1978}, pages = {443-454}, zbl = {0398.20061}, url = {http://dml.mathdoc.fr/item/GDZPPN001252941} }
Demlová, M. On groups of units in a special class of monoids.. Semigroup forum, Tome 16 (1978) pp. 443-454. http://gdmltest.u-ga.fr/item/GDZPPN001252941/