Al-Hawasy, jamil Amir, Haider H. Diwan, and Waffa F. keidan. “The Continuous Classical Optimal Control Problems for Quaternary Elliptic Partial Differential Equations”. Ibn AL-Haitham Journal For Pure and Applied Sciences 37, no. 3 (July 20, 2024): 369–378. Accessed July 24, 2024. https://jih.uobaghdad.edu.iq/index.php/j/article/view/3339.