1. http://americanhistory.si.edu/lighting/20thcent/invent20.htm#in3.
2. R.L. Coble, Transparent Alumina and Method of Preparation, Patent No. US3026210, 1962.
3. A. Dobrusskin, G. Marsen, High-Pressure Sodium Discharge Lamp, Patent No. US4490642, 1984.
4. Transparent ceramic lamp envelope materials;Wei;J. Phys. D: Appl. Phys.,2005
5. Gelcasting and pressureless sintering of translucent alumina ceramics;Mao;J. Am. Ceram. Soc.,2008