Primitive Commutative Association Schemes with a Non-symmetric Relation of Valency 3

Let (X, {Ri}0⩽i⩽d) be a primitive commutative association scheme. If there is a non-symmetric relation Ri with valency 3, then the cardinality of X is equal to either p or p2 where p is an odd prime. Moreover, if |X|=p then (X, {Ri}0⩽i⩽d) is isomorphic to a cyclotomic scheme.