The two-nucleon potential, with the necessary invariance requirements, is assumed to be a quadratic function of momentum: v=-V0J1(r)- (λM) p.J2(r)p, where J1(r) and J2(r) are two short-range functions. For simplicity -J2(r) is assumed to be a square well of unit depth. The Schrödinger equation is solved (neglecting Coulomb forces) for three different choices of J1(r). Numerical results for the phase shifts are given for these three potentials (v1, v2, and v3) for the singlet S, D, and G states. Reasonably good fits are obtained.