Khalid Latrach and Abdelkader DEHICI (2000) Relatively Strictly Singular Perturbations, Essential Spectra, and Application to Transport Operators. Journal of Mathematical Analysis and Applications , 252(2), 767–789, Elsevier
Khalid Latrach and Abdelkader DEHICI (2000) Relatively Strictly Singular Perturbations, Essential Spectra, and Application to Transport Operators. Journal of Mathematical Analysis and Applications , 252(2), 767–789, Elsevier