1. A. Katz andH. J. Lipkin:Phys. Rev. Lett.,7, 44 (1963).
2. N. A. Törnqvist:Phys. Lett.,69 B, 193 (1977).
3. C. Bemporard:Proceedings of the 1977 International Conference on Lepton and Photon Interactions at High Energies (Hamburg, 1977), p. 165; andF. Laplamche:Proceedings of the 1977 International Conference on Lepton and Photon Interactions at High Energies (Hamburg, 1977), p. 189.
4. See,e.g., review byK. Gottfried:Proceedings of the 1977 International Conference on Lepton and Photon Interactions at High Eenergies (Hamburg, 1977), p. 667.
5. See,e.g., review byA. de Rujula andR. L. Jaffe: talk at theMeson Spectroscopy Conference Northeastern University, August 1977, Harward preprint (1977).