- Correspondence to Dr Gunnar Gudmundsson, Department of Respiratory Medicine, Landspitali University Hospital, Reykjavik IS-108, Iceland;
- Received 26 August 2017
- Revised 11 December 2017
- Accepted 18 December 2017
- Published online 9 January 2018.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.