Acknowledgments

Part of the theoretical results on QED radiative corrections to collisions here summarized have been obtained in collaboration with G. Passarino whom we would like to thank. Many stimulating discussions with D. Babusci and A. Zallo about radiative Bhabha scattering at DANE are acknowledged. We are also grateful to INFN, Sezione di Pavia, for having provided computer resources and, in particular, to V. Filippini and A. Fontana for having allowed the use of IBM RISC/350.