@article{DMGT_2012_32_4_a13,
     author = {Goddard, Wayne and Xu, Honghai},
     title = {The s-packing chromatic number of a graph},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {795--806},
     publisher = {mathdoc},
     volume = {32},
     number = {4},
     year = {2012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_2012_32_4_a13/}
}