. 2007 Jun 12;4(6):e202. doi: 10.1371/journal.pmed.0040202
© 2007 Steingart et al.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
Figure 1. Flow Diagram for Study Selection.
