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. 2021 Jul 13;43:e2021045. doi: 10.4178/epih.e2021045

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©2021, Korean Society of Epidemiology

This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Figure 1. — Flow diagram representing the process of the review. ISI, Web of Science; NYAM, New York Academy of Medicine; SIGLE, System for Information on Grey Literature in Europe. ¹Includes irrelevant articles, no reliable or overlapped data. ²Includes conference papers, reviews, books, editorials, letters, oral presentation, correspondence, communications and posters.