@article{DMGT_2019_39_1_a6,
     author = {Chen, Xiaodan and Hao, Guoliang and Volkmann, Lutz},
     title = {Bounds on the {Signed} {Roman} {k-Domination} {Number} of a {Digraph}},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {67--79},
     publisher = {mathdoc},
     volume = {39},
     number = {1},
     year = {2019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_2019_39_1_a6/}
}