1. Finitistic dimension and a homological generalization of semi-primary rings;Bass, Hyman;Trans. Amer. Math. Soc.,1960
2. N. Bourbaki, Algèbre commutative, Chapitre II, Hermann, Paris, 1960.
3. International Series of Monographs on Pure and Applied Mathematics;Fuchs, L.,1960
4. Semi-perfect modules;Mares, Erika A.;Math. Z.,1963