Mohammed Kadhim, Karrar. “Solvability of an Unbounded Operator Equation”. Journal of Al-Qadisiyah for Computer Science and Mathematics 16, no. 2 (June 30, 2024): Math. 56–61. Accessed December 20, 2024. https://jqcsm.qu.edu.iq/index.php/journalcm/article/view/1553.