Ekhad, Shalosh B., and Doron Zeilberger. “The Number of Solutions of $X^2=0$ in Triangular Matrices Over $GF(q)$”. The Electronic Journal of Combinatorics 3, no. 1 (December 1, 1995): R2. Accessed March 31, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v3i1r2.