. 2017 Dec 8;14(12):1537. doi: 10.3390/ijerph14121537
© 2017 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 1.
Search results and excluded/included studies.