. 2013 Jun 20;13:64. doi: 10.1186/1471-2377-13-64
Copyright © 2013 Bertens 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 2.
Flowchart of the study design.