@article {demange2006approximation, title = {On the approximation of Min Split-coloring and Min Cocoloring.}, journal = {J. Graph Algorithms Appl.}, volume = {10}, number = {2}, year = {2006}, pages = {297{\textendash}315}, author = {Demange, Marc and Ekim, Tinaz and de Werra, Dominique and others} }