HERAIZ, T.; AMMAR, A.; JERIBI, A. Essential approximate point and essential defect spectrum of a sequence of linear operators in Banach spaces. Methods of Functional Analysis and Topology, [S. l.], v. 25, n. 4, p. 373–380, 2019. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/739. Acesso em: 15 dec. 2025.