A sum of two locally nilpotent rings may be not nil

[1]  M. Ferrero,et al.  On rings which are sums of two subrings , 1989 .

[2]  P. Wauters,et al.  Radicals of semigroup rings of commutative semigroups , 1986, Mathematical Proceedings of the Cambridge Philosophical Society.

[3]  O. Kegel.  Zur Nilpotenz gewisser assoziativer Ringe , 1963 .