Baktoft, Henrik http://orcid.org/0000-0002-3644-4960
Gjelland, Karl Øystein http://orcid.org/0000-0003-4036-4207
Økland, Finn
Thygesen, Uffe Høgsbro
Article History
Received: 12 June 2017
Accepted: 6 October 2017
First Online: 30 October 2017
Competing Interests
: The authors declare that they have no competing interests.