BEKKER, M. B.; CIMA, J. A. On a localization of the spectrum of a complex Volterra operator. Methods of Functional Analysis and Topology, [S. l.], v. 25, n. 1, p. 12–14, 2019. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/709. Acesso em: 15 dec. 2025.