Slezeviciene, R., and J. Steading. “On Exponential Sums Related to the Circle Problem”. Ukrains’kyi Matematychnyi Zhurnal 56, no. 10 (October 25, 2004): 1405–1418. Accessed December 5, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/3853.