Dildabek, G., M. B. Ivanova, and M. A. Sadybekov. “ON ROOT FUNCTIONS OF NONLOCAL DIFFERENTIAL SECOND-ORDER OPERATOR WITH BOUNDARY CONDITIONS OF PERIODIC TYPE”. Journal of Mathematics, Mechanics and Computer Science 112, no. 4 (December 31, 2021). Accessed December 22, 2024. https://bm.kaznu.kz/index.php/kaznu/article/view/963.