Faaborg, P M
Christensen, P
Krassioukov, A
Laurberg, S
Frandsen, E
Krogh, K
Article History
Received: 10 October 2013
Revised: 27 January 2014
Accepted: 3 February 2014
First Online: 29 April 2014
Competing interests
: The authors declare no conflict of interest.