Louigi Addario-Berry Robert E. L. Aldred Ketan Dalal Bruce A. Reed Vertex colouring edge partitions. 237-244 2005 94 J. Comb. Theory, Ser. B 2 http://dx.doi.org/10.1016/j.jctb.2005.01.001 db/journals/jct/jctb94.html#Addario-BerryADR05