“Asymptotics of solutions of boundary-value problems for linear singularly perturbed systems of differential equations in the case of a multiple spectrum of the boundary matrix”, НК, vol. 21, no. 4, pp. 444–456, Dec. 2018, Accessed: Jan. 21, 2026. [Online]. Available: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/921