“Browder essential approximate pseudospectrum and defect pseudospectrum on a Banach space: doi:10.17398/2605-5686.34.1.29”, Extr. Math., vol. 34, no. 1, p. 29–40, Jun. 2019, Accessed: Dec. 22, 2024. [Online]. Available: https://revista-em.unex.es/index.php/EM/article/view/2605-5686.34.1.29