Abstract
The momentum-moment formulation [Ann. Phys. (NY), 164, 47 (1985)] of Goedert and Lewis [J. Math. Phys. 28, XXX (1987)] and the momentum-resonance formulation of Lewis and Leach are used to study one-dimensional, time-dependent potentials that admit invariants which are rational functions of momentum with two or three simple poles. New examples are presented.