1. See for instance:J. Wess:Nuovo Cimento,18, 1086 (1960);G. Mack, andA. Salam:Ann. of Phys.,53, 174 (1969).
2. J. Wess:Nuovo Cimento,14, 527 (1959).
3. See for instance:R. E. Marshak, Riazuddin andC. P. Ryan:Theory of Weak Interactions in Particle Physics (New York, 1969).
4. G. Mack:Nucl. Phys.,5 B, 499 (1968).
5. B. Renner:Current Algebras and Their Applications (London, 1968), p. 14;R. Oehme:Ann. of Phys.,33, 108 (1965).