Knudsen, Per Kristian http://orcid.org/0000-0002-8076-6553
Gammelsrud, Karianne Wiger
Alfsnes, Kristian
Steinbakk, Martin
Abrahamsen, Tore G.
Müller, Fredrik
Bohlin, Jon
Article History
Received: 5 October 2017
Accepted: 14 December 2017
First Online: 10 January 2018
Competing Interests
: The authors declare that they have no competing interests.