Makarov, V. “Biorthogonal Polynomials and Their Properties. Direct and Inverse Statements”. Ukrains’kyi Matematychnyi Zhurnal 77, no. 10 (September 30, 2025): 629–639. Accessed December 5, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/9381.