. 2019 May 9;14(5):e0216743. doi: 10.1371/journal.pone.0216743
© 2019 van Dijck et al
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Fig 1. Flow chart of the article selection process.
