Král’, Daniel, and Douglas B. West. “Chromatic Number for a Generalization of Cartesian Product Graphs”. The Electronic Journal of Combinatorics 16, no. 1 (June 19, 2009): R71. Accessed March 16, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v16i1r71.