F. J. Correa Restrepo, “Economical Valoration of Enviromental Services in the Valle de Aburra”, Semest. Econ., vol. 5, no. 9, Jun. 2001, Accessed: Aug. 06, 2026. [Online]. Available: https://revistas.udem.edu.co/index.php/economico/article/view/1359