VOLCHKOV, V. V. Spherical means on Euclidean spaces. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 10, p. 1310–1315, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4817. Acesso em: 5 dec. 2025.