De Bruyn, Bart. “A Combinatorial Characterization of Extremal Generalized Hexagons”. The Electronic Journal of Combinatorics 29, no. 4 (December 16, 2022): P4.46. Accessed March 27, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v29i4p46.