1. U.S. Department of Energy. Energy efficiency and renewable energy. The History of Solar. 〈https://www1.eere.energy.gov/solar/pdfs/solar_timeline.pdf〉 [Accessed 29 March 2016].
2. Oklahoma Mesonet. Mesonet sites. 〈https://www.mesonet.org/index.php/site/sites/station_names_map#〉 [Accessed 23 February 2016].
3. Oklahoma Legislature. Constitution of the State of Oklahoma. Article IX section 18, Corporations.
4. Oklahoma Corporation Commission (OCC). Chapter 35: Electric Utility Rules. Vol. 31(24); 2014. 〈http://www.occeweb.com/rules/Ch%2035%20Electric%20Rules%20eff%209-12-2014%20Searchable.pdf〉 [Accessed 20 November 2015].
5. Oklahoma Corporation Commission (OCC). Electricity Prices for Oklahoma Gas and Electric Company; 2015.