@article{GDZPPN001264028, title = {Direct products of cyclic semigroups and unions of groups.}, journal = {Semigroup forum}, volume = {51}, year = {1995}, pages = {223-232}, zbl = {0828.20048}, url = {http://dml.mathdoc.fr/item/GDZPPN001264028} }
Jackson, D.C. Direct products of cyclic semigroups and unions of groups.. Semigroup forum, Tome 51 (1995) pp. 223-232. http://gdmltest.u-ga.fr/item/GDZPPN001264028/