1. Ampere, A. M. Memoires sur l'Electrodynamic Vol. 1, 25 (Gauthier-Villars, Paris, 1885).
2. Bush, V. J. Math. Phys. 5, 129 (1926).
3. Cleveland, F. F. Phil. Mag. 25, 416 (1936).
4. O'Rahilly, A. Electromagnetic Theory Vol. 1, 102 (Dover, New York, 1965).
5. Whittaker, E. History of the Theories of Aether and Electricity Vol. 1, 84 (Thomas Nelson, London, 1951).