. 2012 Mar 19;9:14. doi: 10.1186/1477-7517-9-14
Copyright ©2012 Niccols et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Figure 1.
Flow diagram of studies screened, assessed, and included.