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2. Representation Theory of Finite Groups and associative Algebras;Curtis,1962
3. P. M. Cohn “Morita Equivalence and Duality,” Queen Mary-College, Mathematics notes, London.
4. Commutative subdirectly irreducible rings;Divinsky,1957
5. The lattice of submodules of a module over a noncommutative ring;Feller;Trans. Amer. Math. Soc.,1956