S. C. Forbes, J. M. Holroyd-Leduc, M. J. Poulin, and D. B. Hogan, “Effect of Nutrients, Dietary Supplements and Vitamins on Cognition: a Systematic Review and Meta-Analysis of Randomized Controlled Trials”, Can Geriatr J, vol. 18, no. 4, pp. 231–245, Oct. 2015.