1. S. Fubini: in theProceedings of the XVII International Conference on High-Energy Physics (London, 1974), p. VI-11;A. Pais andG. E. Uhlenbeck:Phys. Rev.,79, 145 (1950).
2. H. Yukawa:Proc. Phys. Math. Soc. Japan,17, 48 (1935).
3. Most solutions of the Yang-Mills gauge fields do not satisfy these conditions. See, for example,T. T. Wu andC. N. Yang: inProperties of Matter under Unusual Conditions, edited byH. Mark andS. Fernbac (New York, N. Y., 1969), p. 349;Phys. Rev. D,12, 3845 (1975);13, 3233 (1976);M. Ikeda andY. Miyachi:Prog. Theor. Phys.,27. 474 (1962);J. P. Hsu:Phys. Rev. Lett.,36, 646, 1515 (1976).
4. A. Pais andG. E. Uhlenbeck:Phys. Eev.,79, 145 (1950).
5. J. P. Hsu:Phys. Rev. D,8, 2610 (1973);J. P. Hsu andJ. A. Underwood:Phys. Rev. D,12, 620 (1975).