Bleka, Øyvind http://orcid.org/0000-0001-8456-1507
Wisløff, Torbjørn
Dahlberg, Pål Skage
Rolseth, Veslemøy
Egeland, Thore
Article History
Received: 7 November 2017
Accepted: 9 April 2018
First Online: 7 May 2018
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.