Y. Q Yahya, Nada, and Heba S. N. Abdullah. “Optimize the Maximum Values Mr (2, Q) for Parentheses in (, K, R in PG (2, Q)”. Journal of Education and Science (JES) 24, no. 2 (June 1, 2011): 159–179. Accessed August 6, 2025. https://ojs.uomosul.edu.iq/index.php/edusj/article/view/24476.