Some Photocontrol Reading

American National Standard Institute. Standard for Roadway Lighting Equipment -- locking-type photocontrol devices and mating receptacles -- physical and electrical interchangeability and testing. ANSI/NEMA Publication C136.10, 1996.

Howell, E.K. "Photoelectric controls for Street Lights," Electrical Engineering. October, 1961, pp. 780-785.

Illuminating Engineering Society of North America. "The Correlation Between Horizontal and Vertical North Sky Illuminance in the Range Between 1 and 5 Foot-candle," IES Journal. Summer, 1992.

Illuminating Engineering Society of North America. DG-13 Design Guide for Photocontrol Selection. New York, New York

Thomas & Betts. HPS Servicing Guide. Thomas & Betts, 1992, pp.16-18 and 26.

United States Naval Observatory: Tables of Sunrise, Sunset, and Twilight - United States Government Printing Office, Washington, D.C. 1962.

Underwriter's Laboratories, Inc. Standard for Safety -- Plug-in, Locking Type Photo-controls for use with Area Lighting. UL Publication 773-1982.