1. Rosser, W. G. V., Classical Electromagnetism via Relativity ( Butterworths, London, 1968 ), p. 265.
2. Vybiral, B., Jour. Phys. D: Appl. Phys., Vol. 22, p. 1 (1989).
3. Jefimenko, O. D., Electricity and Magnetism, 2nd Edition (Electric Scientific, Star City, W. V., 1989), p. 516, or see the 1st Edition (Appleton Century Crofts, 1966 ), p. 516.
4. Panofsky, W. K. H. and Phillips, M., Classical Electricity and Magnetism, 2nd Edition (Addison-Wesley, Reading, Mass., 1962 ), p. 363.
5. Jackson, J. D., Classical Electrodynamics, 2nd Edition (John Wiley, New York, 1975 ). p. 672.