The following organizations provide research material on phosphates, fertilizers and population growth:

International Fertilizer Industry Association (www.fertilizer.org)

World Phosphate Institute (www.imphos.org)

U.S. Geological Survey, Phosphate statistics (http://minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/)

International Plant Nutrition Institute (www.ipni.net)

Food and Agriculture Organization (FAO) (www.fao.org)

United Nations, Population Division, Department of Economic and Social Affairs (http://esa.un.org/unpp)

Canadian Fertilizer Institute (www.cfi.ca)

The Fertilizer Institute (www.tfi.org)

Fertilizer 101 (www.fertilizer101.org)