IVASHCHUK, O. V.; ZADEREI, P. V. On necessary conditions for the convergence of Fourier series. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 63, n. 7, p. 960–968, 2011. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2777. Acesso em: 5 dec. 2025.