Some remarks on (k-1)-critical subgraphs of k-critical graphs, Combinatorica 15, 469-474, 1995.
August 7, 1997. Tommy R. Jensen
T.R. Jensen and G.F. Royle, Small graphs of chromatic number 5 - a computer search, J. Graph Theory 19, 107-116, 1995.
August 12, 1997. Tommy R. Jensen
X.-Y. Su, On complete subgraphs of color-critical graphs, Discrete Math. 143, 243-249, 1995.
X.-Y. Su, Complete (k-1)-subgraphs of k-critical graphs, J. Combin. Math. Combin. Comput. 18, 186-192, 1995.
August 26, 1997. Tommy R. Jensen