C, Eze, A.T Imam, M. Balarabe, and Olaiya O. O , trans. “Graph-Theoretic Characterizations of Quasi-Idempotents in Full Order-Preserving Transformation Semigroup”. Babylonian Journal of Mathematics 2025 (May 28, 2025): 88–91. Accessed October 20, 2025. https://mesopotamian.press/journals/index.php/BJM/article/view/809.