الشمرتي حامد سعد, and حربي هبـــة فاضل. “Comparison Branch and Bound Algorithm With Penalty Function Method for Solving Non-Linear Bi-Level Programming With Application”. Journal of Economics and Administrative Sciences 26, no. 119 (April 30, 2020): 444–457. Accessed May 3, 2025. https://www.jeasiq.uobaghdad.edu.iq/index.php/JEASIQ/article/view/1893.