Yang, Qianqian, Aida Abiad, and Jack H. Koolen. “An Application of Hoffman Graphs for Spectral Characterizations of Graphs”. The Electronic Journal of Combinatorics 24, no. 1 (January 20, 2017): #P1.12. Accessed May 15, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v24i1p12.