Luong, Duc-Tam, Thu-Loan Vu Thi, and Thi-Ngoan Dang. 2025. “A Lagrange Function Approach to Study Second-Order Optimality Conditions for Infinite-Dimensional Optimization Problems”. HPU2 Journal of Science: Natural Sciences and Technology 4 (01):20-30. https://doi.org/10.56764/hpu2.jos.2025.4.01.20-30.