1. E.S. Abers and B.W. Lee, Physics Reports 9C, no 1. S. Coleman in: Laws of Hadronic Matter, Erice July 1973, ed. by A. Zichichi, Academic Press, New York and London.
2. H.B. Nielsen and P. Olesen, Nucl. Phys. B61 (1973) 45, ibidem B160 (1979) 380.
3. B. Zumino, in Renormalization and Invariance in Quantum Field Theory, ed. E.R. Caianiello, Plenum Press, New York, p. 367.
4. G. ’t Hooft, Nucl. Physics B153 (1979) 141.
5. G. ’t Hooft, Nucl. Physics B138 (1978) 1.