Ospanov К. .; Moldagali Е. . CORRECTNESS CONDITIONS FOR FOURTH ORDER DIFFERENTIAL EQUATIONS WITH VARIABLE COEFFICIENTS. Bulletin of Abai KazNPU. Series of Physical and Mathematical sciences, Almaty, Kazakhstan, v. 90, n. 2, p. 116–123, 2025. DOI: 10.51889/2959-5894.2025.90.2.010. Disponível em: https://bulletin-phmath.kaznpu.kz/index.php/ped/article/view/2343. Acesso em: 9 may. 2026.