APA (6th ed.):
ProCon.org. (2009, July 31). Alternative Energy and Fossil Fuel Timeline. Retrieved from https://www.procon.org/alternative-energy-and-fossil-fuel-timeline/
[Editor's Note: The APA citation style requires double spacing within entries.]
Chicago (17th ed.):
ProCon.org, "Alternative Energy and Fossil Fuel Timeline," ProCon.org. last modified July 31, 2009. https://www.procon.org/alternative-energy-and-fossil-fuel-timeline/.
MLA (8th ed.):
ProCon.org, "Alternative Energy and Fossil Fuel Timeline." ProCon.org. 31 July 2009, www.procon.org/alternative-energy-and-fossil-fuel-timeline/
[Editor’s Note: The MLA citation style requires double spacing within entries.]
Turabian (8th ed.):
ProCon.org. "Alternative Energy and Fossil Fuel Timeline." ProCon.org. Last modified on July 31, 2009. Accessed January 15, 2021. https://www.procon.org/alternative-energy-and-fossil-fuel-timeline/