Figure 1
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA
Group (2009). Preferred Reporting Items for Systematic Reviews and
Meta-Analyses: The PRISMA Statement. PLoS Med 6(7): e1000097.
doi:10.1371/journal.pmed1000097. For more information, visit
www.prisma-statement.org.