Ortega, Digna, and José Contreras. “Determinants of Energy Efficiency: Evidence from the Brics Group (1990-2018)”. Semestre Económico 24, no. 57 (August 16, 2022): 282–319. Accessed July 7, 2026. https://revistas.udem.edu.co/index.php/economico/article/view/4114.