Vitamin D and Respiratory Tract Infections: A Systematic Review and Meta-Analysis of Randomized Controlled Trials Bergman, Peter ; Lindh, Åsa U. ; Björkhem-Bergman, Linda ; Lindh, Jonatan D. Abstract Publication: PLoS ONE Pub Date: June 2013 DOI: 10.1371/journal.pone.0065835 Bibcode: 2013PLoSO...865835B