1. Tenth International Conference on Cosmic Rays, Calgary, 1967: Can. Journ. Phys.,46 (1968);Proceedings of the International Conference on Expectations for Particle Reactions at the New Accelerators, April 1970, Wisconsin preprint, and references quoted there.
2. L. Bertocchi, S. Fubini andM. Tonin:Nuovo Cimento,25, 626 (1962);D. Amati, A. Stanghellini andS. Fubini:Nuovo Cimento,26, 6 (1962);L. Bertocchi, E. Predazzi, A. Stanghellini andM. Tonin:Nuovo Cimento,27, 913 (1963).
3. S. J. Chang andR. Rajaraman:Phys. Rev.,183, 1517 (1969);V. N. Akimov, D. S. Chernavskii, I. M. Dremin andI. I. Royzen:Nucl. Phys.,14 B, 285 (1969);I. G. Halliday: ICTP 69/11 (Imperial College preprint) (April 1970).
4. S. Fubini:Strong Interactions and High-Energy Physics, edited byR. G. Moorhouse (Edinburgh, 1963);A. Bassetto:Nuovo Cimento,32, 1321 (1964).
5. I. G. Halliday:Nuovo Cimento,60 A, 177 (1969).