As a Reply to the Comment by Luckinsky et al. [preceding paper, Phys. Rev. E 53, 4240 (1996)] on the paper by Kim and Lee [Phys. Rev. E 52, 473 (1995)], we point out that the formation of zero-dispersion nonlinear resonance can always be observed in a relativistic hard oscillator driven by a periodic force. We also report results of a computation of resonance energies for a driven relativistic Duffing oscillator using the formula suggested by Luchinsky et al.