Tonheim, Aleksander Nygård http://orcid.org/0000-0003-2882-2922
Babic, Ankica http://orcid.org/0000-0002-7532-6828
Chapter History
First Online: 30 May 2018
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest. The study has been approved by the Norwegian data protection official (NSD). All participants signed an informed consent form.