On the generalized ward identity

J. C. Ward:Phys. Rev.,77, 293 (1950);78, 182 (1950);Proc. Phys. Soc,64, 54 (1951).

T. D. Lee:Phys. Rev.,95, 1329 (1954);H. S. Green:Proc. Phys. Soc,66, 873 (1953);L. D. Landau andI. M. Khalatnikov:J.E.T.P.,29 89 (1955);English Translation,2, 69 (1956).

G. KÄllén:Helv. Phys. Acta,25, 417 (1952);H. Lehmann:Nuovo Cimento,11, 342 (1954);M. Gell-Mann andF. E. Low:Phys. Rev.,95, 1300 (1954).

H. A. Tolhoek andS. R. deGroot:Physica,17, 1 (1951).