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. 2021 Aug 23;9:713487. doi: 10.3389/fpubh.2021.713487

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Copyright © 2021 Xia, Yao, Wang, Chen and Wang.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

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Contributions of different countries/regions to the research studies regarding coronavirus disease-2019 (COVID-19). (A) The number of publications, citation frequency (×0.05), and H-index (×5) of the top 20 countries or regions with the highest number of publications. (B) Bibliometric analysis of citations by country. Different colors indicate different clusters, and the size of circles reveals the number of citations. (C) The number of publications regarding COVID-19 worldwide. (D) Density map of countries.