. 2018 Aug 12;2018:9481475. doi: 10.1155/2018/9481475
Copyright © 2018 Qinglian Wang et al.
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Figure 1.
Flowchart of the study selection process.