Lucantoni, C
Krishnan, R G
Gehrchen, M
Hallager, D W
Biering-Sørensen, F
Dahl, B
Article History
Received: 10 June 2015
Revised: 26 November 2015
Accepted: 15 December 2015
First Online: 16 February 2016
Competing interests
: The authors declare no conflict of interest.