Aboulker, P., G. Aubian, P. Charbit, and S. Thomassé. “($\overrightarrow{P_6}$, Triangle)-Free Digraphs Have Bounded Dichromatic Number”. The Electronic Journal of Combinatorics, Vol. 31, no. 4, Dec. 2024, p. P4.60, doi:10.37236/11838.