1. See, for example, T.P. Cheng, L.F. Li: Gauge theory of elementary particle physics. Oxford: Clarendon Press 1984
2. J. Bjorken, S.D. Drell: Relativistic quantum fields. New York: McGraw-Hill 1965
3. N.N. Bogoliubov, D.V. Shirkov: Introduction to the theory of quantized fields. New York: Wiley Interscience 1959
4. K. Fujikawa: Phys. Rev. D 21 (1980) 2848
5. See, for example, K. Shizuya, H. Tsukahara: Z. Phys. C 31 (1986) 553