Korek, Michal
Johansson, Christer
Svensson, Nina
Lind, Tomas
Beelen, Rob
Hoek, Gerard
Pershagen, Göran
Bellander, Tom
Article History
Received: 18 December 2015
Accepted: 2 May 2016
First Online: 3 August 2016
Competing interests
: The authors declare no conflict of interest.