1. J. A. Wheeler andR. P. Feynman:Rev. Mod. Phys.,17, 157 (1945); cf. alsoD. T. Pegg:Rep. Prog. Phys.,38, 1339 (1975), and the literature therein.
2. J. D. Jackson:Classical Electrodynamics, 2nd Edition (New York, N. Y., 1975), p. 780, 5, 566.
3. R. P. Feynman, R. B. Leighton andM. Sands:Lectures on Physics, Vol.2 (Reading, Mass., 1965), p. 15, 26.
4. P. Gosar:Nuovo Cimento B,65, 329 (1981).
5. F. Rohrlich:Classical Charged Particles (Reading, Mass., 1965), p.4.