1. A. C. Scott, F. Y. F. Chu andD. W. McLaughlin:Proc. IEEE,61, 1449 (1973).
2. For a criticism of the concept of point particle see for instance the Einstein’s notes inAlbert Einstein:Philosopher-Scientist, edited byA. Schilpped (Evanston, III., 1949).
3. For an early idea of the relevance of a stochastic approach applied to cosmic electrodynamics see:W. Ritz andA. Einstein:Zeits. Phys.,10, 323 (1909). The fact thatA. Einstein was never satisfied by the nondeterministic character of quantum theory is of course well known. For recent revivals of these idea see for instance:C. Frederick:Phys. Rev. D,13, 3183 (1976). For the less unconventional idea that elementary particles be related to solitons in the framework of quantum field theory see:L. D. Faddeev:JETP Lett. 21,138 (1975). The original idea of a relationship between (what are now called) solitons and elementary particles is duo toT. H. R. Skyrme:Prov. Roy. Soc,262 A, 237 (1961).
4. F. Calogero andA. Degasperis:Lett. Nuovo Cimento,16, 425, 434 (1976). The reader is assumed to be familiar with these two papers, whose notation is used below and whose equations are referred to by their number preceded by I or II.
5. F. Calogero andA. Degasperis:Nuovo Cimento,39 B, 1 (1977).