Funding for this research was provided by:
Universitetet i Tromsø
Received: 11 October 2017
Accepted: 21 February 2018
First Online: 7 March 2018
Ethics approval and consent to participate
: According to Norwegian legislation, this project did not need ethics approval. The Norwegian Centre for Research Data (NSD) has been notified about the project. All participants gave their written consent to participate.
: Not applicable.
: Both authors declare that there are no competing interests.
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