References
- LoudenW. E. and SchmidtK., “High-Pressure Sodium Discharge Arc Lamps”, Illuminating Engineering, Vol. 60, December 1965, p. 696.
- HannemanR. E.,LoudenW. E., and McVeyC. I., “High-Pressure Sodium Lamp”, Illuminating Engineering, Vol. 64, March 1969, p. 162.
- CottonH., Electric Discharge Lamps, Chapman and Hall Ltd., 1946.