@article{ADM_2017_24_1_a4,
     author = {M. Atapour and S. Norouzian and S. M. Sheikholeslami and L. Volkmann},
     title = {Twin signed domination numbers in directed graphs},
     journal = {Algebra and discrete mathematics},
     pages = {71--89},
     publisher = {mathdoc},
     volume = {24},
     number = {1},
     year = {2017},
     language = {en},
     url = {https://geodesic-test.mathdoc.fr/item/ADM_2017_24_1_a4/}
}