Engerud, H
Tangen, I L
Berg, A
Kusonmano, K
Halle, M K
Øyan, A M
Kalland, K H
Stefansson, I
Trovik, J
Salvesen, H B
Krakstad, C
Article History
Received: 13 February 2014
Revised: 11 April 2014
Accepted: 23 April 2014
First Online: 22 May 2014
Competing interests
: The authors declare no conflict of interest.