1. R. Gatto: inSpringer Tracts in Modern Physics, vol.39 (Berlin, 1965).
2. This process will be investigated with Adone by a group consisting ofG. Barbiellini, B. Borgia, M. Conversi, R. Del Fabbro, E. Di Capua, C. Pellegrini, L. Tau andS. Tazzari. We are grateful to Prof.M. Conversi for information on the project.
3. Y. S. Tsai: SLAC.PUB.-117, May 1965.
4. E. Etim andB. Touschek: LNF. 66/10 Frascati.
5. G. Putzolu:Nuovo Cimento,20, 542 (1961).