1. Institute of Medicine. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements (The National Academies Press, 2006).
2. World Health Organisation & Food Agriculture Organization. Vitamin and Mineral Requirements in Human Nutrition (WHO, 2004).
3. Institute of Medicine. Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc (The National Academies Press, 2001).
4. De Backer, G. & Hautvast, J. EURRECA (EURopean micronutrient RECommendations Aligned) network of excellence. Eur. J. Clin. Nutr. 64, S1 (2010).
5. Stamm, R. A. & Houghton, L. A. Nutrient intake values for folate during pregnancy and lactation vary widely around the world. Nutrients 5, 3920–3947 (2013).