USGS, water.usgs.gov, Last Updated 4-11-2007.
Sallamander Concepts, www.anyvitamins.com, Last Updated March 26, 2007 .
Weis, Peter, http://www.truehealth.org, Last Updated March 2000.
Strum, Stephen M.D., http://www.realtime.net, Last Updated September 1994.
Dr. Romeyn, Mary, http://www.thebody.com, Last Updated February 1998.
Wiley InterScience, http://www3.interscience.wiley.com, Last Updated 2004.
HighBeam� Research, Inc., http://www.encyclopedia.com
Encyclopedia Britannica, Inc., http://www.britannica.com
RxList Inc., http://www.rxlist.com