1. J. J. Sakurai:Ann. of Phys.,11, 1 (1960).
2. J. J. Sakurai:Phys. Rev. Lett.,9, 472 (1962).
3. E. Armenteros, L. Montanet, D. R. O. Morrison, S. Nilsson, A. Shapiro, J. Vandermeulen, Ch. d’Andlau, A. Astier, J. Ballam, C. Ghesquière, B. P. Gregory, D. Rahm, P. Rivet andF. Solmitz:Proc. of the 1962 International Conference on High-Energy Physics at CERN (Geneva, 1962), p. 351;G. B. Chadwick, W. T. Davies, M. Derrick, C. J. B. Hawkins, J. H. Mulvey, D. Radojicic, C. A. Wilkinson, M. Cresti, S. Limentani andR. Santangelo: loc. cit., p. 69.
4. Y. Eisenberg:Phys. Rev. Lett.,10, 60 (1963) for further details.
5. G. B. Chadwick et al.: loc. cit., p. 69 and p. 73;Phys. Rev. Lett.,10, 621 (1963).