Text and Data Mining valid from 2018-06-19
Received: 8 February 2018
Accepted: 8 June 2018
First Online: 19 June 2018
Ethics approval and consent to participate
: The study was approved by the Norwegian Centre for Research Data (NSD no: 54963), and permission was given by a university located in Norway. All participants signed a letter of consent to participate in the study.
: Not applicable
: The authors declare that they have no competing interests.
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