KALYBAY, A.; OINAROV, R. Oscillatory and spectral analysis of higher-order differential operators. Eurasian Mathematical Journal, [S. l.], v. 16, n. 3, p. 20–41, 2025. DOI: 10.32523/2077-9879-2025-16-3-20-41. Disponível em: https://emj.enu.kz/index.php/main/article/view/821. Acesso em: 24 oct. 2026.