Lê , C. K., Nguyễn , T. L., & Nguyễn , . M. Đức C. (2013). Solving the problem of electric generator units combination with multiple fuel option using lagrange multiplier theory. Journal of Technical Education Science, 8(3), 10–16. Retrieved from https://www.jte.edu.vn/index.php/jte/article/view/741