@article{CMJ_2005__55_2_a17,
     author = {Zelinka, Bohdan},
     title = {Signed domination numbers of directed graphs},
     journal = {Czechoslovak Mathematical Journal},
     pages = {479--482},
     publisher = {mathdoc},
     volume = {55},
     number = {2},
     year = {2005},
     mrnumber = {2137154},
     zbl = {1081.05042},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMJ_2005__55_2_a17/}
}