. 2018 Jul 25;15(8):1579. doi: 10.3390/ijerph15081579
© 2018 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.
Flow diagram of the data collection process.