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2. United States Geological Survey (USGS) Earth Resources Observation Systems (EROS) Data Center. 1999, 1 km Land Cover Characterization Database, Database Revisions for Latin America. Sioux Falls, SD: USGS EDC. Unpublished data.

3. World Conservation Monitoring Centre. 1996, Original Forest Map, Current Forest Map. Cambridge, UK: WCMC.

4. UNEP-WCMC (United Nations Environment Programme - World Conservation Monitoring Centre). 1998, Global Wetland Distribution. Cambridge, UK: UNEP-WCMC.

5. Environmental Systems Research Institute. 1997, ArcAtlas: Our Earth Database.

6. US Army Corps of Engineers. 1996, National Inventory of Dams.

7. Global Environment Monitoring System. 1995, Water Quality of World River Basins.

8. UNEP - ISRIC (International Soil Reference and Information Centre). 1990, Global Assessment of Soil Degradation (GLASOD). Wageningen, Netherlands:

9. Environmental Systems Research Institute. 1992, ArcWorld 1:3M. Continental Coverage. Redlands, CA: ESRI.

10. Center for Natural Resources, Energy and Transport of the Department of Economic and Social Affairs of the United Nations. 1978, Register of International Rivers. Oxford, UK: Pergamon Press.

11. Center for International Earth Science Information Network (CIESIN); Columbia University; International Food Policy and Research Institute; and World Resources Institute. 2000, Gridded Population of the World, Version 2. Palisades, NY: CIESIN, Columbia University.
Available On-line at: Source Link.

12. United Nations Urban Agglomerations. 1996, Urban Agglomerations.

13. UNEP - Birkbeck College of the University of London. 1990, World Cities Population Database. London, UK:

14. World Conservation Monitoring Centre. 1999, Fish Species Data: Endemics, Diadromous, Introduced, Threatened.

15. World Conservation Union (IUCN). 1996, 1996 IUCN Red List of Threatened Animals.

16. World Conservation Monitoring Centre. 1999, Protected Areas Database. Cambridge, UK: WCMC. Unpublished data.

17. Stattersfield, A.J., M.J. Crosby, A.J. Long, and D.C. Wege. 1998. "Endemic Bird Areas of the World: Priorities for Biodiversity Conservation". Birdlife Conservation Series No. 7:

18.