A comment on: "Further restrictions on the structure of finite   DCI-groups"
  A finite group R is a CI-group if, whenever S and T are subsets of R with the Cayley graphs Cay(R,S) and Cay(R,T) isomorphic, there exists an automorphism x of R with S^x=T.   The classification of CI-groups is an open problem in the theory of Cayley graphs and is closely related to the isomorphism problem for graphs. This paper is a contribution towards this classification, as we show that every dihedral group of order 6p, with p>3 prime, is a CI-group. 
Edward Dobson, Joy Morris, Pablo Spiga
math.CO math.GR