APA (7th ed.) Citation

Gupta, H. K. (2007). Geothermal energy: An alternative resource for the 21st century. Elsevier.

Chicago Style (17th ed.) Citation

Gupta, Harsh K. Geothermal Energy: An Alternative Resource for the 21st Century. Amsterdam, the Netherlands ; Boston: Elsevier, 2007.

MLA (9th ed.) Citation

Gupta, Harsh K. Geothermal Energy: An Alternative Resource for the 21st Century. Elsevier, 2007.