1. Anonymous: Title 21. Food and Drugs. Subpart B. Fortification Policy 104.2, part d, 1-3. Electronic Code of Federal Regulations. [ http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=5839e8fdbe957776cd79b1747d6e0925&rgn=div5&view=text&node=21:2.0.1.1.4&idno=21 ]
2. Institute of Medicine (U.S.). Panel on Macronutrients., Institute of Medicine (U.S.). Standing Committee on the Scientific Evaluation of Dietary Reference Intakes.: Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. 2005, Washington, D.C. , National Academies Press, xxv, 1-972, 1259-1331.
3. Atwater WO: The potential energy of food. The chemistry of food. III. Century Magazine. 1887, 34: 397-405.
4. Pearsall J, Trumble W: The Oxford English reference dictionary . 2002, Oxford, England ; New York , Oxford University Press, 2nd ed., rev.
5. Hargrove JL: History of the calorie in nutrition. The Journal of nutrition. 2006, 136 (12): 2957-2961.