Al-bar, Jehan A., Ahmad N. Al-kenani, Najat M. Muthana, Cheryl E. Praeger, and Pablo Spiga. 2016. “Finite Edge-Transitive Oriented Graphs of Valency Four: A Global Approach”. The Electronic Journal of Combinatorics 23 (1), P1.10. https://doi.org/10.37236/4779.