SHAPIRO, M.; VINNIKOV, V.; YUDITSKII, P. Finite difference operators with a finite band spectrum. Математическая физика, анализ, геометрия, Харків, Україна, v. 11, n. 3, p. 331–340, 2004. Disponível em: https://mag.ilt.kharkiv.ua/index.php/mag/article/view/m11-0331e. Acesso em: 22 лис. 2024.