VARBANETS, P. D.; KIRBAT, S. A. On the mean value of the function $\overline{S}_k(n)$. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 63, n. 4, p. 448–458, 2011. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2730. Acesso em: 6 dec. 2025.