Heebøll, S
Poulsen, M K
Ornstrup, M J
Kjær, T N
Pedersen, S B
Nielsen, S
Grønbæk, H
Handberg, A
Article History
Received: 23 August 2016
Revised: 15 November 2016
Accepted: 20 November 2016
First Online: 5 December 2016
Competing interests
: The authors declare no conflict of interest.