1. J.D. Jackson, Classical Electrodynamics, 3rd edition (John Wiley and Sons, New York, 1999) pp. 775-776
2. B.N. Taylor (Editor), NIST Special Publication 330: The International System of Units (SI) (National Institute of Standards and Technology, Gaithersburg, MD, 2001). See also the SI Brochure, http://www.bipm.org/utils/common/pdf/si_brochure_8.pdf (in particular, 2.1.1)
3. A. Ernst, J.P. Hsu, Chin. J. Phys. 39, 211 (2001) It is interesting to note that Voigt proposed the idea of the universal speed of light in 1887 long before Poincaré and Einstein wrote their milestone papers in 1905
4. L. Hsu, J.P. Hsu, D.A. Schneble, Nuovo Cimento B 111, 1229 (1996)
5. J.P. Hsu, L. Hsu, Nuovo Cimento B 112, 575 (1997)