1. G. Cocconi:Phys. Rev.,111, 1699 (1958);R. Hagedorn:Nuovo Cimento,15, 434 (1960);B. Peters:Nuovo Cimento,23, 88 (1962);G. Bozóki, E. Fenyves, A. Feenkel, E. Gombosi andP. Surányi:Nuovo Cimento,24, 29 (1962).
2. R. Hagedorn andJ. Ranpt:Suppl. Nuovo Cimento,6, 169 (1968);R. Hagedorn:Nuovo Cimento,56 A, 1027 (1968).
3. K. G-. Wilson:Some experiments on multiple production, preprint CLNS-131, November 1970 and September 1973, Laboratory of Nuclear Studies, Cornell University, Ithaca, N. Y., 14850.
4. G. Bellettini: papers presented at theXIII International Cosmic Ray Conference,Denver, Colo., 1973, to be published;
5. G. Bellettini:Besults from the Pisa-Stony Brook-ISRexperiment, CERN report and invited paper at theV International Conference on High-Energy Collisions, Stony Brook, 23–24 August 1973 (Fig. 25). See also literature quoted inA. Jabs:Phys. Rev. D,7, 3368 (1973).