APA (7th ed.) Citation

Petty, S., & Porro, G. (2007). Updated U.S. geothermal supply characterization. National Renewable Energy Laboratory.

Chicago Style (17th ed.) Citation

Petty, S., and G. Porro. Updated U.S. Geothermal Supply Characterization. Golden, CO: National Renewable Energy Laboratory, 2007.

MLA (9th ed.) Citation

Petty, S., and G. Porro. Updated U.S. Geothermal Supply Characterization. National Renewable Energy Laboratory, 2007.