Valencia Ochoa, G., Alvarez, J. N., & Acevedo, C. (2019). Research Evolution on Renewable Energies Resources from 2007 to 2017: A Comparative Study on Solar, Geothermal, Wind and Biomass Energy. International Journal of Energy Economics and Policy, 9(6), 242–253. Retrieved from https://www.econjournals.com/index.php/ijeep/article/view/8051