Rr. Andruszkiewicz et Er. Puczylowski, ON COMMUTATIVE IDEMPOTENT RINGS, Proceedings of the Royal Society of Edinburgh. Section A. Mathematics, 125, 1995, pp. 341-349
We study the problem when a ring which is an extension of a commutativ
e idempotent ring by a commutative idempotent ring is commutative. In
particular, we answer Sands' question showing that the class of commut
ative idempotent rings whose every homomorphic image has zero annihila
tor is a maximal but not the largest radical class consisting of commu
tative idempotent rings.