Funding for this research was provided by:
Forskningsrådet i Sydöstra Sverige
Article History
Received: 17 December 2018
Accepted: 17 May 2019
First Online: 31 May 2019
Ethics approval and consent to participate
: The study was approved by the local ethics committee of Linköping University, Sweden (Dnr: 2011 72/31), and completion of the postal survey was deemed to be the agreement of participants' informed consent.
: Not applicable.
: The authors declare that they have no competing interests.