1. For reviews of foundation and applications of perturbative QCD see, for example: J. Ellis, Lectures presented at the Les Houches Summer School 1976; H. D. Politzer, Physics Reports 14, 129 (1974).
2. For a discussion of this point I am grateful to Dr. J. Kwieczinsky from Cracov, Poland.
3. A comprehensive review can be found in H.D.I. Abarbanel, J.B. Bronzan, R.L.Sugar, and A.R.White, Physics Reports 21c, 121 (1975)
4. M. Moshe, Physics Reports 37c, 257 (1978) and references therein.
5. M. Gell-Mann and M.L. Goldberger, Phys. Rev. Letters 9, 275 (1962); M. Gell-Mann, M.L. Goldberger, F.E. Low, and F. Zachariasen, Phys. Letters 265 (1963); M. Gell-Mann, M. Goldberger, F.E. Low, E. Marx,and F. Zachariasen, Phys. Rev. 133,B, 145 (1964); M. Gell-Mann, M.L. Goldberger, F. E. Low, V.Singh, and F. Zachariasen, Phys. Rev. 133,B, 949 (1964),