United Nations, United Nations Population Division,
Department of Economic and Social Affairs, “The
World at Six Billion,” http://www.cbu.edu/~esalgado/
BIOL107/UNpopulationfactoids.doc,(accessed
November 7, 2011)
United Nations, “Report of the World Commission
on Environment and Development: Our Common
Future, Brundtland Commission Report, 1987,”
http://www.un-documents.net/wced-ocf.htm,
(accessed November 8, 2011)
United States Environmental Protection Agency,
“What is Sustainability,” http://www.epa.gov/
sustainability/basicinfo.htm#sustainability (ac-
cessed November 4, 2011)
United States Geological Survey, “USGS Mineral
Commodity Summary, 2011,” http://minerals.
usgs.gov/minerals/pubs/mcs/2011/mcs2011.
pdf, (accessed November 3, 2011)
United States of America, “National Security Strategy
of The United States of America, 1988”
2point6billion.com, “Population Forecast: India
to Overtake China by 2025,” http://
http://www.2point6billion.com/news/2011/06/29/
population-forecast-india-to-overtake-china-
by-2025-9640.html (accessed November 3, 2011)