Luong, Duc-Tam, Thu-Loan Vu Thi, and Thi-Ngoan Dang. “A Lagrange Function Approach to Study Second-Order Optimality Conditions for Infinite-Dimensional Optimization Problems”. HPU2 Journal of Science: Natural Sciences and Technology 4, no. 01 (April 28, 2025): 20–30. Accessed April 30, 2025. https://sj.hpu2.edu.vn/index.php/journal/article/view/277.