Parasyuk О. S. “Analytical Continuation of Expansions in Hegenbauer Polynomials and Its Application to the Investigation of the Properties of the Scattering Amplitude”. Ukrains’kyi Matematychnyi Zhurnal 18, no. 4 (June 28, 1966): 126–128. Accessed April 14, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/8323.