. 2013 Jul 18;8(7):e68939. doi: 10.1371/journal.pone.0068939
© 2013 Huang 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 4. Begg’s funnel plot for publication bias.
