1. J. Schwinger:Phys. Lett.,24 B, 9 (1967).
2. J. Wess andB. Zumino:Lagrangian method for chiral symmetries, New York University preprint, June 1967.
3. C. Isham:Nuovo Cimento,59 A, 356 (1969).
4. S. Coleman, C. G. Callan, J. Wess andB. Zumino:The structure of phenomenological Lagrangians, I, II, New York University preprint.
5. This point is discussed in ref. (4).S. Coleman, C. G. Callan, J. Wess andB. Zumino:The structure of phenomenological Lagrangians, I, II, New York University preprint.