Araujo-Pardo, Gabriela, Juan José Montellano-Ballesteros, Mika Olsen, and Christian Rubio-Montiel. “The Diachromatic Number of Digraphs”. The Electronic Journal of Combinatorics 25, no. 3 (September 21, 2018): #P3.51. Accessed May 1, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v25i3p51.