@article{10_37236_9906,
     author = {Pierre Aboulker and Pierre Charbit and Reza Naserasr 	},
     title = {Extension of {Gy\'arf\'as-Sumner} conjecture to digraphs},
     journal = {The electronic journal of combinatorics},
     year = {2021},
     volume = {28},
     number = {2},
     doi = {10.37236/9906},
     zbl = {1470.05049},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/9906/}
}