http://drlwilson.com/Articles/ZINC.htm
http://examine.com/supplements/Vitamin+D/#thingstoknow
http://examine.com/supplements/Magnesium/#thingstoknow
http://examine.com/supplements/Zinc/#thingstoknow
http://examine.com/supplements
http://lpi.oregonstate.edu/mic/minerals/zinc
http://lpi.oregonstate.edu/mic/minerals/magnesium
http://lpi.oregonstate.edu/mic/vitamins/vitamin-D
http://lpi.oregonstate.edu/mic/vitamins/niacin
http://articles.mercola.com/sites/articles/archive/2013/12/08/magnesium-health-benefits.aspx
http://www.easy-immune-health.com/magnesium-and-vitamin-d.html
http://www.foodkrazy.com/post/read/discussionId/9/t/10-tips-on-how-to-stay-young-forever-secrets-revealed-by-a-shao