Loebl, Martin, and Petr Somberg. “Discrete Dirac Operators, Critical Embeddings and Ihara-Selberg Functions”. The Electronic Journal of Combinatorics 22, no. 1 (January 9, 2015): P1.10. Accessed March 15, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v22i1p10.