Koolen, Jack H., Joohyung Kim, and Jongyook Park. “Distance-Regular Graphs With a Relatively Small Eigenvalue Multiplicity”. The Electronic Journal of Combinatorics 20, no. 1 (January 7, 2013): #P1. Accessed May 25, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v20i1p1.