1. R. W. Brown andI. J. Muzinich: Brookhaven Nat. Lab. Int. Rep. BNL 15713 (1971);N. Artega-Romero, A. Jaccarini, P. Kessler andJ. Parisi:Lett. Nuovo Cimento,4, 933 (1970);Phys. Rev. D,3, 1569 (1971);S. J. Brodsky, T. Kinoshita andH. Terazawa:Phys. Rev. Lett.,25, 972 (1970);Phys. Rev. D,4, 1532 (1971);V. N. Baier andV. S. Fadin:Phys. Lett.,35 B, 156 (1971);M. Greco:Nuovo Cimento,4 A, 689 (1971).
2. F. E. Low:Phys. Rev.,120, 582 (1960);F. Calogero andC. Zemach:Phys. Rev.,120, 1860 (1960).
3. C. Bernardini: Rapporteur talk on Adone results:The International Conference on Electrons and Photons Interaction, Cornell, August 1971; Frascati Int. Rep. LNF 71/63 (1971).
4. V. E. Balakin, G. I. Budker, E. V. Pakhtusova, V. A. Sidorov, A. N. Skrinsky, G. M. Tumaikin andA. G. Khabakhpaskev:Phys. Lett.,34 B, 328, 663 (1971); preprint of the Institute of Nuclear Physics 54–71, Novosibirsk, 1971.
5. C. Bacci, R. Baldini-Celio, G. Capon, C. Mencuccini, G. Penso, G. P. Murtas, A. Reale, G. Salvini andM. Spinetti:Lett. Nuovo Cimento,2, 73 (1971);Phys. Lett. (to be published).