Le, Ngoc-Kien, Van-Nghi Tran, and Van-Hao Nguyen. “Some Applications of Directional Subdifferentials at Infinity to Vector Optimization Problems”. HPU2 Journal of Science: Natural Sciences and Technology 5, no. 01 (April 28, 2026): 76–86. Accessed April 29, 2026. https://sj.hpu2.edu.vn/index.php/journal/article/view/579.