Volchkov, V. V., and I. M. Savost’yanova. “Analog of the John Theorem for Weighted Spherical Means on a Sphere”. Ukrains’kyi Matematychnyi Zhurnal 65, no. 5 (May 25, 2013): 611–619. Accessed April 19, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2445.