“…24 It was shown that in the case of one first-order and one third-order integral, the only classical superintegrable systems were known ones ͑like V = ␣r 2 or V = ␣r −1 ͒ for which the third-order integral was the product, on the Poisson commutator, of a first-and second-order one. However, in the quantum case, a new superintegrable potential of this type exists, namely V 1 ͑x , y͒ = ͑ប ͒ 2 k 2 sn 2 ͑ x , k͒, where sn͑ x , k͒ is a Jacobi elliptic function.…”