Hong Danh P, Hoang Dung H. LINEAR APPROXIMATION ASSOCIATED WITH THE SYSTEM OF NONLINEAR FUNCTIONAL- INTEGRAL. VNUHCM Journal of Science and Technology Development [Internet]. 31Dec.2003 [cited 3Sep.2025];6(12):15-. Available from: http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/3390