GRONA , V. L. Uniform convergence of the Fourier spherical sums differentiated by the function. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 43, n. 1, p. 47–53, 1991. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/9304. Acesso em: 17 feb. 2026.