KELDIBEKOVA, A.B. Solvability of a semi-periodic boundary value problem for a third order differential equation with mixed derivative. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 98, n. 2, p. 84–99, 2020. DOI: 10.31489/2020m2/84-99. Disponível em: https://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/363. Acesso em: 1 sep. 2025.