1. Energy Information Administration - EIA - Official Energy Statistics from the U.S. Government., “How much electricity is used for lighting in the United States? - FAQ - U.S. Energy Information Administration (EIA),” 2017, (12 June 2017).
2. American households use a variety of lightbulbs as CFL and LED adoption increases;Woodward,2017
3. U.S. Department of Energy - Office of Energy Efficiency & Renewable Energy., “Lighting Basics | Department of Energy,” 2013, (1 March 2017).
4. Production of light;Hoffman,1912