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. 2022 Feb 10;9:779722. doi: 10.3389/fmed.2022.779722

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Copyright © 2022 Yang, Yin, Peng, Zhang, Li, Cui, Xia, Huang and Li.

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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Country/region analysis. (A) The top 20 most productive countries/regions for EP research, (B) Collaborations of the countries/regions in EP field, (C) Network map of countries/regions (T = 9) related to EP research.