1. Can we raise grain yields fast enough?;Brown;Worldwatch,1997
2. Engleman LeRoy 1996 Sustaining Water: Population and the Future of Renewable Water Supplies
3. EPA 1994 National Water Quality Inventory, 1992: Report to Congress
4. Eco-farming in Fiji;Kane;Worldwatch,1997
5. The fate of nitrogen and phosphorus at the land-sea margin of the North Atlantic Ocean;Nixon;Biogeochemistry