. 2014 Apr 23;7:265. doi: 10.1186/1756-0500-7-265
Copyright © 2014 Piso 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 selection process (PRISMA flow diagram).