Forberg, Torunn
Sjulstad, Eli Bjørnø
Bakke, Ingrid
Olsen, Yngvar
Hagiwara, Atsushi
Sakakura, Yoshitaka
Vadstein, Olav
Article History
Received: 4 August 2015
Accepted: 19 January 2016
First Online: 15 February 2016
Competing interests
: The authors declare no competing financial interests.