A discrete analogue of the second-order differential operator withvariable coefficient. Uzbek Mathematical Journal, [S. l.], v. 69, n. 3, p. 161–167, 2025. DOI: 10.29229/uzmj.2025-3-17. Disponível em: https://uzmj.mathinst.uz/index.php/uzmj/article/view/24.. Acesso em: 11 sep. 2025.