Ishkin Х. On conditions for the finiteness of the spectrum of a second order differential operator with integral boundary conditions: . Journal of Mathematics, Mechanics and Computer Science, [S. l.], v. 124, n. 4, p. 26–37, 2025. DOI: 10.26577/JMMCS2024-v124-i4-a2. Disponível em: https://bm.kaznu.kz/index.php/kaznu/article/view/1521. Acesso em: 15 jan. 2025.