Andrei Kelarev Cheryl E. Praeger On transitive Cayley graphs of groups and semigroups. 59-72 2003 24 Eur. J. Comb. 1 http://dx.doi.org/10.1016/S0195-6698(02)00120-8 db/journals/ejc/ejc24.html#KelarevP03