1. Generalized Inverse of Matrices and Its Applications;Rao,1971
2. Introduction to Matrices with Applications in Statistics;Graybill,1969
3. Rings and Ideals;McCoy;Carus Monograph,1948
4. On regular rings;Neumann;Proc. Nat. Acad. Sci.,1936
5. The Theory of Rings;McCoy,1965