1. F. Laplanche, in: Proceedings 1977 International Symposium on Lepton and Photon Interactions at High Energies, p. 189 C. Bemporad, in: Proceedings 1977 International Symposium on Lepton and Photon Interactions at High Energies, p. 165 S.D. Protopescu, New states below 2.2 GeV in e+e− annihilation, BNL preprint-23612.
2. Experimental situation is far from definitive (private communication).
3. High energy leptonic interactions;Renard,1974