1. Hutton JL, Ashcroft R. What does “systematic” mean for reviews of methods? In: Black N, Brazier J, Fitzpatrick R, Reeves B, editors. Health services research methods: a guide to best practice. London: BMJ Publishing Group; 1998. p. 249–54.
2. Cochrane handbook for systematic reviews of interventions. In. Edited by Higgins JPT, Green S, Version 5.1.0 edn: The Cochrane Collaboration; 2011.
3. Centre for Reviews and Dissemination: Systematic reviews: CRD’s guidance for undertaking reviews in health care. York: Centre for Reviews and Dissemination; 2009.
4. Liberati A, Altman DG, Tetzlaff J, Mulrow C, Gotzsche PC, Ioannidis JPA, Clarke M, Devereaux PJ, Kleijnen J, Moher D. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate healthcare interventions: explanation and elaboration. BMJ. 2009;339:b2700–0.
5. Barnett-Page E, Thomas J. Methods for the synthesis of qualitative research: a critical review. BMC Med Res Methodol. 2009;9(1):59.