RASHID, M. H. M. Subscalarity of $k$-quasi-class $A$ operators. Methods of Functional Analysis and Topology, [S. l.], v. 25, n. 2, p. 177–188, 2019. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/721. Acesso em: 15 dec. 2025.