REFERENCES
- Akbari , S. , Mohammadian , A. , Radjavi , H. , Raja , P. ( 2006 ). On the diameters of commuting graphs . Linear Algebra Appl. 418 : 161 – 176 .
- Kokol Bukovšek , D. , Košir , T. , Novak , N. , Oblak , P. ( 2007 ). Products of commuting nilpotent operators . Electron. J. Linear Algebra 16 : 237 – 247 .
- Novak , N. ( 2009 ). Sums of commuting square-zero transformations . Linear Algebra Appl. 431 : 1768 – 1773 .
- Communicated by M. Cohen.