1. N. Cabibbo, G. Parisi andM. Testa:Lett. Nuovo Cimento,4, 35 (1970).
2. See, for example,J. D. Bjorken: rapporteur’s talk given at theInternational Symposium on Electron and Photon Interaction at High Energies (Bonn, 1973).
3. R. Schwitters: Rapporteurs talk at theStanford Conference, August 1975.
4. T. Appelquist andH. Georgi:Phys. Rev. D.,8, 4000 (1973);A. Zee:Phys. Rev. D,8, 4038 (1973). See also,H. D. Politzer:Phys. Rep. 14 C, 130 (1974).
5. J. Schwinger:Particles, Sources and Fields, Vol.2 (New York, N. Y., 1973).