VOLCHKOV, V. V.; SAVOST’YANOVA, I. M. Smoothing of the Singularities of Functions Whose Integrals over the Balls on a Sphere are Zero. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 67, n. 2, p. 272–278, 2015. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1979. Acesso em: 7 apr. 2025.