1. J. G. Vargas,Found. Phys. 11, 235 (1981).
2. H. P. Robertson,Rev. Mod. Phys. 21, 378 (1949).
3. J. G. Vargas, ?Nonrelativistic paraMaxwellian Electrodynamics,?Found. Phys. To be published.
4. J. D. Bjorken and S. D. Drell,Relativistic Quantum Mechanics (McGraw-Hill, New York, 1963).
5. S. D. Drell,Physica 96A, 3 (1979).