1. The minimum Hadwiger number for graphs with a given mean degree of vertices;Kostochka;Metody Diskret. Anal.,1982
2. Random planar graphs;McDiarmid;J. Combin. Theory Ser. B,2005
3. An extremal function for contractions of graphs;Thomason;Math. Proc. Cambridge Philos. Soc.,1984
4. D. Welsh, Lecture at the NZIMA Conference on Combinatorics and Its Applications, Lake Taupo, New Zealand, December 2004