A. B. Mahmood and A. S. Mahmood, “Secret-Word by e-Abacus Diagram I”, Iraqi Journal of Science, vol. 60, no. 3, pp. 638–646, Mar. 2019, Accessed: Jul. 05, 2026. [Online]. Available: https://www.ijs.uobaghdad.edu.iq/index.php/eijs/article/view/675