KAL’MENOV, T. S.; TOREBEK, B. T. On an ill-posed problem for the Laplace operator with nonlocal boundary condition. Eurasian Mathematical Journal, [S. l.], v. 8, n. 1, p. 50–57, 2017. Disponível em: https://emj.enu.kz/index.php/main/article/view/654. Acesso em: 30 sep. 2025.