KOZHANOV, A.I.; KOSHANOV, B.D.; SULTANGAZIYEVA, Zh.B.; YEMIR KADY OGLU, A.N.; SMATOVA, G.D. Spectral problem for the sixth order nonclassical differential equations. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 97, n. 1, p. 79–86, 2020. DOI: 10.31489/2020m1/79-86. Disponível em: http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/323. Acesso em: 28 aug. 2025.