Text and Data Mining valid from 2018-05-25
Received: 17 November 2017
Accepted: 14 May 2018
First Online: 25 May 2018
Ethics approval and consent to participate
: The Norwegian Data Inspectorate licensed all data. The Regional Committee for Research Ethics approved the study (REC no. 200005785–7/IAY/400). All the participants gave their written informed consent.
: All the participants gave their written informed consent for publication of the data.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.