HUMBATALIEV, R. Z. On solvability of some boundary value problems for elliptic type operator-differential equations. Eurasian Mathematical Journal, [S. l.], v. 5, n. 4, p. 33–55, 2014. Disponível em: https://emj.enu.kz/index.php/main/article/view/587. Acesso em: 17 sep. 2025.