DOGAN, Nuri Ozgur, and Can Tansel TUGCU. “Energy Efficiency in Electricity Production: A Data Envelopment Analysis (DEA) Approach for the G-20 Countries”. International Journal of Energy Economics and Policy 5, no. 1 (December 26, 2014): 246–252. Accessed April 23, 2024. https://www.econjournals.com/index.php/ijeep/article/view/1043.