Y. Imangaliyev, “ABOUT DIFFERENCE OF SOLUTION SINGULAR DISTURBED AND UNDISTURBED BOUNDARY PROBLEMS”, Rec.Contr.Phys., vol. 34, no. 3, pp. 122–125, Nov. 2018, Accessed: Sep. 10, 2026. Available: https://bph.kaznu.kz/index.php/zhuzhu/article/view/1028