MAHMOOD, Awreng B.; MAHMOOD, Ammar S. Secret-Word by e-Abacus Diagram I. Iraqi Journal of Science, [S. l.], v. 60, n. 3, p. 638–646, 2019. Disponível em: https://www.ijs.uobaghdad.edu.iq/index.php/eijs/article/view/675.. Acesso em: 7 dec. 2025.