Vieth Reinhold, Bischoff-Ferrari Heike, Boucher Barbara J, Dawson-Hughes Bess, Garland Cedric F, Heaney Robert P, Holick Michael F, Hollis Bruce W, Lamberg-Allardt Christel, McGrath John J, Norman Anthony W, Scragg Robert, Whiting Susan J, Willett Walter C, Zittermann Armin
Am J Clin Nutr. 2007 Mar;85(3):649-50. doi: 10.1093/ajcn/85.3.649.