Varbanets, S. P. “General Kloosterman Sums over Ring of Gaussian integers</B&gt;”. Ukrains’kyi Matematychnyi Zhurnal 59, no. 9 (September 25, 2007): 1179-1200. Accessed April 25, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3381.