Utnes, Ane L G
Sørum, Vidar
Hülter, Nils
Primicerio, Raul
Hegstad, Joachim
Kloos, Julia
Nielsen, Kaare M
Johnsen, Pål J
Article History
Received: 24 October 2014
Revised: 30 January 2015
Accepted: 6 February 2015
First Online: 7 April 2015
Competing interests
: The authors declare no conflict of interest.