supported by National Natural Science Foundation of China (Grant No.10871021);the Specialized Research Fund for the Doctoral Program of Higher Education in China (Grant No.20060004026)
A regular edge-transitive graph is said to be semisymmetric if it is mot vertex-transitive. By Folkman [J. Combin. Theory 3 (1967), 215-232], there is no semisymmetric graph of order 2p or 2p^2 for a prime p, and by...