1. Y. A. Abramovich, C. D. Aliprantis, An invitation to the operator theory, Graduate Stud. Math 50 (2002).
2. E. A. Alekhno, Spectral properties of band irreducible operators. In: Proceedings Positivity IV–Theory and Application. Dresden (Germany) (2006), pp. 5–14.
3. C. D. Aliprantis, O. Burkinshaw, Positive Operators. Academic Press (1985).
4. V. A. Erovenko, Functional Analysis: Spectral and Fredholm Properties of Linear Operators, (Russian) Minsk, BSU (2002).
5. T. Kato, Perturbation Theory for Linear Operators. Springer-Verlag (1976).