Gregers, J
Gréen, H
Christensen, I J
Dalhoff, K
Schroeder, H
Carlsen, N
Rosthoej, S
Lausen, B
Schmiegelow, K
Peterson, C
Article History
Received: 18 June 2014
Revised: 12 October 2014
Accepted: 5 November 2014
First Online: 13 January 2015
Competing interests
: The authors declare no conflicts of interest.