REFERENCES
- Anderson , D. D. , Camillo , V. ( 1999 ). Semigroups and rings in whose zero products commute . Comm. Algebra 27 ( 6 ): 2847 – 2852 .
- Cartan , H. , Eilenberg , S. ( 1973 ). Homological Algebra . Princeton Landmarks in Mathematics. Originally published in 1956 . Princeton : Princeton University Press , 1956 .
- Cohn , P. M. ( 1999 ). Reversible rings . Bull. London Math. Soc. 31 ( 6 ): 641 – 648 .
- Haghany , A. , Varadarajan , K. ( 1999 ). Study of formal triangular matrix rings . Comm. Algebra 27 ( 11 ): 5507 – 5525 .
- Han , J. , Nicholson , W. K. ( 2001 ). Extensions of clean rings . Comm. Algebra 29 ( 6 ): 2589 – 2595 .
- Kim , N. K. , Lee , Y. ( 2003 ). Extensions of reversible rings . J. Pure Appl. Algebra 185 : 207 – 223 .
- Krempa , J. , Niewieczeral , D. ( 1977 ). Rings in which annihilators are ideals and application to semigroup rings . Bull. Acad. Polon. Sci. Ser. Sci. Math. Astronom, Phy. 25 : 851 – 856 .
- Lambek , J. ( 1971 ). On the representation of modules by sheaves of factor modules . Canad. Math. Bull. 14 ( 3 ): 359 – 368 .
- Nicholson , W. K. ( 1977 ). Lifting idempotents and exchange rings . Trans. Amer. Math. Soc. 229 : 269 – 278 .
- Sherman , C. ( 1981 ). Cartan maps, clean rings, and unique factorization . J. Algebra 70 ( 1 ): 102 – 115 .
- Communicated by R. Wisbauer.