Center for Combinatorics,LPMC-TJKLC, Nankai University,Tianjin 300071, China; College of Science, Tianjin University of Technology,Tianjin 300384, China. and College of Science, Tianjin University of Technology,
Tianjin 300384, China.
Abstract:
The authors investigate locally primitive bipartite regular
connected graphs of order $18p$. It is shown that such a graph
is either arc-transitive or isomorphic to one of the Gray graph and the Tutte $12$-cage.