1. C. E. Detar, D. Z. Fredman andG. Veneziano:Phys. Rev. D,4, 909 (1971);T. T. Chou andC. N. Yang:Phys. Rev. Lett.,25, 1072 (1970).
2. C. G. Callan andD. J. Gross: Princeton preprint (1972);
3. H. Fritzsch andP. Minkowski: CERN preprint TH 1575 (1972).
4. $$\overline W _1 $$ and $$\overline W _2 $$ are defined as in ref. (2)C. G. Callan andD. J. Gross: Princeton preprint (1972);
5. H. Fritzsch andH. Minkowski: CERN preprint TH 1575 (1972), whileW(q) 2 is defined asW