Analytic parametrizations of the non-perturbative Pomeron and QCD-inspired models

11 pages, 2 tables, Presented at the 9th Blois Workshop on Elastic and Diffractive Scattering, Pruhonice, Czech Republic, 9-15 June 2001We consider several classes of analytic parametrizations of hadronic scattering amplitudes, and compare their predictions to all available forward data (proton- proton, antiproton-proton, pion-proton, kaon-proton, photon-proton, photon- photon, sigma-proton). Although these parametrizations are very close for energy larger than 9 GeV, it turns out that they differ markedly at low energy, where a universal Pomeron term ~(ln s)**2 enables one to extend the fit down to 4 GeV