AKHTYAMOV, A.; SADOVNICHY, V.; SULTANAEV, Y. Generalizations of Borg’s uniqueness theorem to the case of nonseparated boundary conditions. Eurasian Mathematical Journal, [S. l.], v. 3, n. 4, p. 10–22, 2012. Disponível em: https://emj.enu.kz/index.php/main/article/view/803. Acesso em: 6 oct. 2025.