Sternemalm, J
Russnes, H G
Zhao, X
Risberg, B
Nord, S
Caldas, C
Børresen-Dale, A L
Stokke, T
Patzke, S
Article History
Received: 22 November 2013
Revised: 24 March 2014
Accepted: 9 May 2014
First Online: 5 June 2014
Competing interests
: The authors declare no conflict of interest.