Text and Data Mining valid from 2018-04-04
Received: 1 November 2017
Accepted: 19 March 2018
First Online: 4 April 2018
Ethics approval and consent to participate
: The study was approved by the Ethical Board in Umeå (Dnr 2014–196-32 M).
: Not applicable.
: The authors declare that they have no competing interests.
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