1.
Karandjulov L. Asymptotic solution of definite class of singularly perturbed linear boundary-value problems for ordinary differential equations. Ann. Sofia Univ. Fac. Math. and Inf. [Internet]. 1999 Dec. 12 [cited 2024 Dec. 4];91:79-95. Available from: https://stipendii.uni-sofia.bg/index.php/fmi/article/view/271