. 2019 Jul 25;16(15):2662. doi: 10.3390/ijerph16152662
© 2019 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.
Year of publication, 2004 to October 2018.