. 2014 Jun 17;14:333. doi: 10.1186/1471-2334-14-333
Copyright © 2014 Weiss 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 credited.
Figure 1.
Literature search and study selection process.