Kim, Dae San, and Seung-Hwan Yang. “A RECURSIVE FORMULA FOR POWER MOMENTS OF 2-DIMENSIONAL KLOOSTERMAN SUMS ASSOCIATED WITH GENERAL LINEAR GROUPS”. Italian Journal of Pure and Applied Mathematics, vol. 34, June 2015, pp. 7-16, https://journals.uniurb.it/index.php/ijpam/article/view/6303.