Mathiesen, S
Uhlving, H H
Buchvald, F
Hanel, B
Nielsen, K G
Müller, K
Article History
Received: 14 November 2013
Revised: 19 June 2014
Accepted: 20 June 2014
First Online: 11 August 2014
Competing interests
: The authors declare no conflict of interest.