Radicals induced by the total of rings. Beidar, K.I.; Wiegandt, R. — 1997 Beiträge zur Algebra und Geometrie
An example of two von Neumann regular rings with nonisomorphic Monta equivalent multiplicative semigroups. A.V. Mikhalev; U. Knauer; K.I. Beidar — 1994 Semigroup forum