Inference for Annotated Logics over Distributive Lattices. - James J. Lu; Neil V. Murray; Heydar Radjavi; Erik Rosenthal; Peter Rosenthal (ISMIS, 2002)

Reducibility of semigroups and nilpotent commutators with idempotents of rank two. - Matjaz Omladic; Heydar Radjavi (Ars Math. Contemp., 2010)