The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration - Liberati, A; Altman, D G; Tetzlaff, J; Mulrow, C; Gøtzsche, P C; Ioannidis, J P; Clarke, M; Devereaux, P J; Kleijnen, J; Moher, D (Plos Medicine, 2009)