Usenko, E. G. (1998) “Criteria for the coincidence of the kernel of a function with the kernels of its Riesz and Abel integral means”, Ukrains’kyi Matematychnyi Zhurnal, 50(12), pp. 1712–1714. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4792 (Accessed: 18May2024).