MASMALIEV, G. M.; KHANMAMEDOV, A. Kh. On conditions for the discreteness of the spectrum of a semiinfinite Jacobi matrix with zero diagonal. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 62, n. 2, p. 285–288, 2010. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2866. Acesso em: 5 dec. 2025.