Khneab , Alaa S., Jamil Amir Al-hawasy, and Ion Chryssoverghi. 2024. “Quaternary Boundary Optimal Control Problem for Quaternary Nonlinear Elliptic System With Constraints”. Al-Mustansiriyah Journal of Science 35 (4): 31-41. https://doi.org/10.23851/mjs.v35i4.1546.