Kostovski, E
Dahm, A E A
Mowinckel, M C
Stranda, A
Skretting, G
Østerud, B
Sandset, P M
Iversen, P O
Article History
Received: 12 August 2014
Revised: 3 December 2014
Accepted: 17 December 2014
First Online: 3 February 2015
Competing interests
: The authors declare no conflict of interest.