1. J. Bowcock andA. Martin:Nuovo Cimento,14, 516 (1959).
2. T. Regge:Nuovo Cimento,14, 951 (1959).
3. R. Blankenbecler, M. L. Goldberger, N. N. Khuri andS. B. Treiman:Ann. Phys. (to be published).
4. S. Mandelstam:Phys. Rev.,112, 1344 (1958).
5. M. Gell-Mann:High Energy Nuclear Physics: Proceedings of the Sixth Annual Rochester Conference (1956), III p. 30. This program has been applied to the potential theory in reference (3) and to quantize theories byS. Mandelstam.