. 2021 Feb 19;18(4):1999. doi: 10.3390/ijerph18041999
© 2021 by the authors.
Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Figure 2.
Flow chart of search strategies and results.