DURNA, N. Subdivision of spectra for some lower triangular double-band matrices as operators on $c_0$. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 70, n. 7, p. 913–922, 2018. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1605. Acesso em: 5 dec. 2025.