1. F. Rohrilich,Classical Charged Particles(Addison-Wesley, Reading, Mass., 1965).
2. A. OBarut,Electrodynamics and Classical Theory of Fields and Particles(Macmillan, New York, 1964).
3. For the definitions of sine- and cosine-integral see, e.g., M. Abramowitz and I. A. Stegun;Handbook of Mathematical Functions(Applied Mathematics Series 55, National Bureau of Standards, Washington, D.C., 1970).
4. We recall that the quadripotential has no direct physical meaning in classical electrodynamics. Only the field strengths are physically measurable quantities.