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. 2021 May 18;291:243–251. doi: 10.1016/j.jad.2021.05.014

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Fig. 1 — Geographic distribution of participants in Shenzhen City, China. The map of China and the inset showing the distribution of participants from ten districts in Shenzhen were obtained from online sources (https://www.wikiwand.com/ and https://wenku.baidu.com/, respectively). Sample sizes are shown below the names of each region.