1. Edge colorings of graphs embeddable in a surface of low genus;Hind;Discrete Math.,1998
2. The chromatic class and location of a graph on a closed surface;Mel'nikov;Mat. Zametki,1970
3. Planar graphs of maximum degree seven are class I;Sanders;J. Combin. Theory B,2001
4. On an estimate of the chromatic class of a p-graph;Vizing;Diskret. Analiz,1964
5. Critical graphs with given chromatic class;Vizing;Diskret. Analiz,1965