some remarks on regular association schemes of order pqr

Let c be a non-thin regular association scheme of order pqr, where p, q and r are any prime numbers. ##using the thin radical and thin residue, we give sufficient conditions for such association scheme to be schurian. ##also, we show that c is isomorphic to the wreath product of two thin regular association schemes of order r and pq, if thin radical and thin residue are equal of order pq