Suda, Sho. “Characterizations of Regularity for Certain $Q$-Polynomial Association Schemes”. The Electronic Journal of Combinatorics 22, no. 1 (January 20, 2015): #P1.12. Accessed May 14, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v22i1p12.