1. L. D. Landau and E. M. Lifshitz,Electrodynamics of Continuous Media (Pergamon Press, Oxford, 1963).
2. L. D. Landau and E. M. Lifshitz,Statistical Physics (Pergamon Press, Oxford, 1970).
3. L. D. Landau and E. M. Lifshitz,The Classical Theory of Fields (Pergamon Press, Oxford, 1971), Chapter 3.
4. L. D. Landau and E. M. Lifshitz,Quantum Mechanics (Pergamon Press, Oxford, 1965), Chapter 15.
5. E. A. Guggenheim,Proc. Roy. Soc. (Lond.) A155, 49 (1936).