ISMAILOV, Z. I.; ÖZTÜRK MERT, R. Normal extensions of a singular differential operator on the right semi-axis. Eurasian Mathematical Journal, [S. l.], v. 5, n. 3, p. 117–124, 2014. Disponível em: https://emj.enu.kz/index.php/main/article/view/582. Acesso em: 20 aug. 2025.