1. The constant transverse-momentum law was first suggested byJ. Nishimura:Soryushiron Kenkyu,12, 24 (1956).
2. The first reference on this point is:A. Bigi, S. Brandt, R. Carrera, W. A. Cooper, A. de Marco, G. R. McLeod, Ch. Peyrou, R. Sosnowski andA. Wrobleski:Int. Conf. on High-Energy Physics, CERN (1962), p. 247.
3. G. Cocconi, J. Koester andD. H. Perkins: UCRL-10022 (1961).
4. J. Orear:Phys. Rev. Lett.,13, 190 (1964).
5. Aachen-Berlin-CERN Collaboration:Phys. Lett.,19, 608 (1965).