[5] Kaplansky, I.: 
Rings of Operators. Mathematics Lecture Note Series, W. A. Benjamin, New York (1968). 
MR 0244778 | 
Zbl 0174.18503 
[6] Kim, C. O., Kim, H. K., Jang, S. H.: 
A study on quasi-duo rings. Bull. Korean Math. Soc. 36 (1999), 579-588. 
MR 1722187 | 
Zbl 0938.16002 
[16] Salem, R. M., Farahat, M. A., Abd-Elmalk, H.: 
PS-modules over Ore extensions and skew generalized power series rings. Int. J. Math. Math. Sci. (2015), Article ID 879129, 6 pages. 
DOI 10.1155/2015/879129 | 
MR 3332121 
[19] Xue, W.: 
Modules with projective socles. Riv. Mat. Univ. Parma, V. Ser. 1 (1992), 311-315. 
MR 1230620 | 
Zbl 0806.16004