@article{DMGT_2020_40_4_a3,
     author = {Volkmann, Lutz},
     title = {The {Double} {Roman} {Domatic} {Number} of a {Digraph}},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {995--1004},
     publisher = {mathdoc},
     volume = {40},
     number = {4},
     year = {2020},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_2020_40_4_a3/}
}