1.
Kopach M, Obshta A, Shuvar B. Both-side approximation of solutions of differential equations. Carpathian Math. Publ. [Internet]. 2009 Dec. 30 [cited 2024 Nov. 22];1(2):172-9. Available from: https://ktipe.pnu.edu.ua/index.php/cmp/article/view/4012