1. Anonymous (2005) APHA, 19th edition, American Public Health Association AWWA, Water Pollution Control Federation, New York
2. Anonymous (1989) National Research Council, Food and Nutrition Board, Recommended Dietary Allowances
3. Anonymous (2001) Dietary reference intakes for vitamin a, vitamin k, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc
4. Anonymous (2004) Agency for toxic substances and disease registry
5. Anonymous (2006) World health organization report, 2006.
http://water.epa.gov/action/advisories/drinking/upload/2009_04_27_criteria_drinking_dwstandards.pdf