NAS 2005: National Academy of Sciences, Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients), Food and Nutrition Board, [Accessed 2012 May 15]. Available from: http://www.nap.edu/openbook.php?record_id=10490&page=680