Text and Data Mining valid from 2018-08-31
Received: 5 December 2017
Accepted: 21 August 2018
First Online: 31 August 2018
Ethics approval and consent to participate
: According to the Dutch Research involving Human Subjects Act (WMO), this study was not subject to an ethical review.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.