Horodets’kyiV, Martynyuk O, Kolisnyk R. On a nonlocal problem for the first-order differential-operator equations. Carpathian Math. Publ. [Internet]. 2022Dec.30 [cited 2023Dec.4];14(2):513-28. Available from: https://journals.pnu.edu.ua/index.php/cmp/article/view/4790