Varbanets, P. D., and S. A. Kirbat. “On the Mean Value of the Function $\overline{S}_k(n)$”. Ukrains’kyi Matematychnyi Zhurnal 63, no. 4 (April 25, 2011): 448-458. Accessed May 4, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2730.