@article{GDZPPN001252828, title = {Radicals of semigroups.}, journal = {Semigroup forum}, volume = {16}, year = {1978}, pages = {299-344}, zbl = {0393.20047}, url = {http://dml.mathdoc.fr/item/GDZPPN001252828} }
Schein, B.M.; Roiz, E.N. Radicals of semigroups.. Semigroup forum, Tome 16 (1978) pp. 299-344. http://gdmltest.u-ga.fr/item/GDZPPN001252828/