Th normal decomposition of lattices and the Krull-Schmidt theorem. Juliusz Brezezinski (1975) Mathematica Scandinavica
The Jacobson radical of some endomorphism rings. Wolfgang Liebert (1973) Journal für die reine und angewandte Mathematik
The p. p. ring and the Pierce sheaf representation of non-commutative rings George Szeto, T. O. To (1980) Mathematica Slovaca