AL-BAR, J. A.; AL-KENANI, A. N.; MUTHANA, N. M.; PRAEGER, C. E.; SPIGA, P. Finite Edge-Transitive Oriented Graphs of Valency Four: a Global Approach. The Electronic Journal of Combinatorics, v. 23, n. 1, p. P1.10, 22 Jan. 2016.