1. J. D. Jackson,Classical Electrodynamics(Wiley, New York, 1962), pp. 98–102.
2. J. O. Hirschfelder, C. F. Curtiss, and R. B. Bird,Molecular Theory of Gases and Liquids(Wiley, New York, 1954), pp. 27, 839.
3. Reference 3, p. 1008. This exception is due to the exact degeneracy of hydrogenic excited states having different spatial charge distributions, giving the perturbed atom an effective dipole moment.
4. The dynamics of the reaction D2++N→ND++D