Sze, S. M. & Ng, K. K. (2007). "Appendix E". Physics of semiconductor devices (Third ed.). New York: Wiley-Interscience. p. 788. ISBN978-0-471-14323-9.
For an introduction to the subject of choices for independent units, see
Jackson, John David (1999). "Appendix on units and dimensions". Classical electrodynamics (Third ed.). New York: Wiley. pp. 775 et seq. ISBN978-0-471-30932-1.