Department of Basic Science, Jundi-Shapur University of Technology, Dezful, Iran.
For two normal edge-transitive Cayley graphs on groups H and K which have no
common direct factor and gcd(jH=H
′j; jZ(K)j) = 1 = gcd(jK=K
′j; jZ(H)j), we consider four
standard products of them and it is proved that only tensor product of factors can be normal