¹ http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1908/

² http://www.nrc.gov/materials/fuel-cycle-fac/ur-enrichment.html

³ http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/enrichment.html

⁴ http://www.nuclearfiles.org/menu/key-issues/nuclear-weapons/basics/weapons-basics.htm

⁵ http://fnic.nal.usda.gov/food-composition/individual-macronutrients-phytonutrients-vitamins-minerals/vitamins-minerals

⁶ http://www.hc-sc.gc.ca/fn-an/nutrition/reference/index-eng.php

⁷ http://reference.medscape.com/drug/calcium-gluconate-344434

⁸ http://www.nobelprize.org/nobel_prizes/physics/laureates/1922/bohr-bio.html

⁹ http://www.biography.com/people/niels-bohr-21010897

¹⁰ http://www.atoms-for-peace.org/