1. M. Greco andY. Srivastava, Nuovo Cimento,18A, 601, 1973.
2. J. D. Bjorken, Proc. VI. Int. Symposium on Electron and Photon Interactions at High Energies, Bonn, 1973 (North-Holland Publ. Co., Amsterdam, 1974) p. 25;J. D. Bjorken andB. L. Ioffe, Talk presented at the Seminar on Quark and Parton Problems, Moscow, 1974 SLAC-PUB-1467, 1974;R. Gatto andG. Preparata, Nucl. Phys.,B67, 362, 1973;F. Elvekjaer andF. Steiner, DESY-preprint, DESY 75/49, 1975;D. C. Fetzer andH. Schlereth, Aachen preprint (1976).
3. A. McDonald, Nucl. Phys.,B75, 343, 1974;R. Gatto andG. Preparata, Lett. Nuovo Cimento,7, 89, 1973;R. Budny andA. McDonald, Physics Letters,B48, 423, 1974;G. V. Dass andG. G. Ross, Physics Letters,B57, 173, 1975;E. Lendvai andL. Palla, ITP-Budapest Rep. No. 354, 1975.
4. G. V. Dass andG. G. Ross, CERN-preprint, Th. 2196-CERN, 1976.
5. R. F. Schwitters, Proc. 1975 Int. Symposium on Lepton and Photon Interactions at High Energies, Stanford, 1975 (SLAC, Stanford, 1975; Ed.: W. T. Kirk) p. 5;B. H. Wiik, in the above volume, p. 69.