. 2015 Jul 14;2:e12. doi: 10.1017/gmh.2015.10
© The Author(s) 2015
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Fig. 1.
Prisma Flow Diagram. Source: Moher et al. (2009).