article by Christer Janson et al published 12 September 2018 in BMC Pulmonary Medicine
author: Cecilie Svanes, Ane Johannessen, Christer Janson, Thorarinn Gislason, Debbie Jarvis, Vivi Schlunssen, Karl A Franklin, Rain Jõgi, Andrei Malinovschi, Linus Schiöler