1. E. L. Lady, ?Slender rings and modules,? Pac. J. Math.,49, No. 2, 397?406 (1973).
2. Sekou Traore, ?Slender modules, slender rings,? Acta Sci. Math. (Szeged),33, 77?80 (1972).
3. M. Huber, On Reflexive Modules and Abelian Groups (Habilitations Schrift), Freiburg (1981).
4. S. V. Rychkov, ?On direct products of Abelian groups,? Dokl. Akad. Nauk SSSR,252, No. 2, 301?302 (1980).
5. S. V. Rychkov, ?On direct products of Abelian groups,? Mat. Sb.,117, No. 2, 266?278 (1982).