@article{DMTCS_2020_22_1_a2,
     author = {Hochst\"attler, Winfried and Schr\"oder, Felix and Steiner, Raphael},
     title = {On the {Complexity} of {Digraph} {Colourings} and {Vertex} {Arboricity}},
     journal = {Discrete mathematics & theoretical computer science},
     publisher = {mathdoc},
     volume = {22},
     number = {1},
     year = {2020-2021},
     doi = {10.23638/DMTCS-22-1-4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.23638/DMTCS-22-1-4/}
}