Mahmood, Ammar S., and Jwan K. Khaleel. “Adding Rows in Main E-Abacus Diagrams”. Iraqi Journal of Science 65, no. 2 (February 29, 2024): 841–852. Accessed June 24, 2026. https://www.ijs.uobaghdad.edu.iq/index.php/eijs/article/view/8664.