Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis
Laura Tripkovic, Helen Lambert, Kathryn Hart, Colin P Smith, Giselda Bucca, Simon Penson, Gemma Chope, Elina Hypponen, Jacqueline Berry, Reinhold Vieth, and Susan Lanham-New, Am J Clin Nutr 2012;95:1357–64