Abd-Elhameed, W.M., and A.M. Al-Sady. “Some Orthogonal Combinations of Legendre Polynomials”. Contemporary Mathematics 5, no. 2 (April 15, 2024): 1522–1551. Accessed April 8, 2025. https://ojs.wiserpub.com/index.php/CM/article/view/3525.