1. World Population Prospects: The 2015 Revision, Key Findings and Advance Tables,2015
2. World Urbanization Prospects: The 2014 Revision, Highlights,2014
3. Review of the Efficiency and Effectiveness of Colombia's Environmental Policieshttp://www.rff.org/files/sharepoint/WorkImages/Download/RFF-Rpt-ColoEPEfficiency.pdf
4. Curva de Rodas and la Pradera Landfill Gas Management Project, Version 3http://www.voksenaasen.no/wp-content/uploads/2016/08/Prosjektinfo_-CDM-2183_Curva-de-Rodas-and-La-Pradera-landfill-gas-management-project.pdf