1. Abdmouleh, F.; Ammar, A.; Jeribi, A.: Pseudo-Browder essential spectra of linear operators and application to a transport equations. Preprint (2012)
2. Browder F.: On the spectral theory of elliptic differential operators. I. Math. Ann. 142, 22–130 (1961)
3. Davies, E.B.: Spectral Theory and Differential Operators. Cambridge Studies in Advanced Mathematics, 42. Camb. Univ. Press, Cambridge (1996)
4. Davies, E.B.: Linear Operators and their Spectra. Cambridge Studies in Advanced Mathematics, 106. Camb. Univ. Press, Cambridge (2007)
5. Dautray, R.; Lions, J.L.: Analyse mathématique et calcul numérique. Tome 9, Masson, Paris, (1988)