1. On colouring the modes of a network;Brooks;Proc. Cambridge Philos. Soc.,1941
2. The structure of k-chromatic graphs;Dirac;Fund, Math.,1953
3. On the structure of 5- and 6-chromatic abstract graphs;Dirac;J. Reine Angew. Math,1964
4. Kritische Graphen I;Gallai;Publ. Math. Inst. Hungar. Acad. Sci.,1963
5. Critical graphs;Gallai,1964