@article{GDZPPN00125720X, title = {Characters and the structure of finite semigroups.}, journal = {Semigroup forum}, volume = {30}, year = {1984}, pages = {211-220}, zbl = {0533.20040}, url = {http://dml.mathdoc.fr/item/GDZPPN00125720X} }
Grassmann, H. Characters and the structure of finite semigroups.. Semigroup forum, Tome 30 (1984) pp. 211-220. http://gdmltest.u-ga.fr/item/GDZPPN00125720X/