Referencia:
Thorlund K, Imberger G, Walsh M, Chu R, Gluud C, Wetterslev J, Guyatt G, Devereaux PJ, Thabane L. The number of patients and events required to limit the risk of overestimation of intervention effects in meta-analysis--a simulation study. PLoS One. 2011;6(10):e25491. doi: 10.1371/journal.pone.0025491. Epub 2011 Oct 18.