Cod liver oil, vitamin A toxicity, frequent respiratory infections, and the vitamin D deficiency epidemic

John J. Cannell, Reinhold Vieth, Walter Willett, Michael Zasloff, John N. Hathcock, John H. White, Sherry A. Tanumihardjo, D. Enette Larson-Meyer, Heike A. Bischoff-Ferrari, Christel J. Lamberg-Allardt, Joan M. Lappe, Anthony W. Norman, Armin Zittermann, Susan J. Whiting, William B. Grant, Bruce W. Hollis, Edward Giovannucci