@article{DMGT_2005_25_1-2_a2,
     author = {Harant, Jochen and Henning, Michael},
     title = {On double domination in graphs},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {29--34},
     publisher = {mathdoc},
     volume = {25},
     number = {1-2},
     year = {2005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_2005_25_1-2_a2/}
}