Seppola, Marit
Bakkemo, Kathrine Ryvold
Mikkelsen, Helene
Myrnes, Bjørnar
Helland, Ronny
Irwin, David M.
Nilsen, Inge W.
Article History
Received: 21 March 2016
Accepted: 31 May 2016
First Online: 21 June 2016
Competing interests
: The authors declare no competing financial interests.