STEPANETS, O. I. Approximation of Convolution Classes by Fourier Sums. New Results. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 54, n. 5, p. 581–602, 2002. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4097. Acesso em: 21 dec. 2025.