Ammar A, Jeribi A, Mahfoudhi K. Measure of noncompactness, essential approximation and defect pseudospectrum. MFAT [Internet]. 2019 Mar. 25 [cited 2026 Feb. 4];25(1):1-11. Available from: https://zen.imath.kiev.ua/index.php/mfat/article/view/708