1. Gustafson, Weidmann, Kato, Wolf, Schechter, Browder, Rakočević and Schmoger essential spectra of the sum of two bounded operators;Abdmouleh;Math. Nachr.,2011
2. Riesz operators and perturbation ideals;Aiena;Note Mat.,1989
3. A. Ben Amar, A. Jeribi, M. Mnif, Some results on Fredholm and semi-Fredholm perturbations and applications, Int. J. Math. Anal. (2011), in press.
4. Operators of Riesz type;Caradus;Pacific J. Math.,1966
5. Linear Operators, Part I. General Theory;Dunford,1958