Spectral properties for polynomial and matrix operators involving demicompactness classes : doi:10.17398/2605-5686.33.1.11. Extracta Mathematicae, [S. l.], v. 33, n. 1, p. 11–32, 2018. Disponível em: https://revista-em.unex.es/index.php/EM/article/view/2605-5686.33.1.11. Acesso em: 24 may. 2026.