. 2019 May 2;2019:6121696. doi: 10.1155/2019/6121696
Copyright © 2019 Jingyi Zhao 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 2.
Risk of bias and applicability concern graph.