. 2021 Sep 10;8:720019. doi: 10.3389/fmed.2021.720019
Copyright © 2021 Lu, Wang, Sun, Zhang, Yan, Wang, Gao, Yin, Wang, Li and Hou.
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Figure 3.
A meta-analysis of ER visits. Df, degrees of freedom; M-H, Mantel–Haenszel.