1. K. Symanzik: inNon-perturbative Field Theory and QCD, edited byR. Iengo, A. Neveu, P. Olesen andG. Parisi (World Scientific Publ. Co., Singapore, 1983), p. 61;Nucl. Phys. B,226, 187, 205 (1983);Commun. Math. Phys.,45, 59 (1975).
2. See, for example,M. Weinstein, S. D. Drell, H. R. Quinn andB. Svetitsky:Phys. Rev. D,22, 1190 (1980).
3. See, for example,B. F. L. Ward:Phys. Rev. D,28, 1215 (1983); Lockheed preprint (1983); SLAC-PUB 3139 (1983);Nuovo Cimento A,97, 299 (1987).
4. See, for example,N. N. Bogoliubov andD. Shirkov:Introduction to the Theory of Quantized Fields (Interscience Publishers, New York, N. Y., 1959);K. Hepp:Commun. Math. Phys.,2, 301 (1966);W. Zimmermann: in1970 Brandeis Lectures on Particle Physics, edited byS. Deser, M. Grisaru andH. Pendleton (M.I.T. Press, Cambridge, Mass., 1970), p. 395, and references therein.
5. J. D. Bjorken andS. D. Drell:Relativistic Quantum Mechanics (McGraw-Hill Book Co., New York, N. Y., 1964).