Citation:Norman AW 1998
From National Cancer Control Policy
Norman AW. Sunlight, season, skin pigmentation, vitamin D, and 25-hydroxyvitamin D: integral components of the vitamin D endocrine system. Am J Clin Nutr 1998 Jun;67(6):1108-10 Available from: http://www.ncbi.nlm.nih.gov/pubmed/9625080.
Critical appraisals