1. University of Belgrade School of Medicine, Internal Medicine Department, Belgrade, Serbia.
2. Clinical Center of Serbia, Teaching Hospital of Pulmonology, Belgrade, Serbia.
3. Faculty of Organizational Sciences, Laboratory of Statistics, Belgrade, Serbia.
a. http://orcid.org/0000-0003-2792-5954; b. http://orcid.org/0000-0002-2212-3648; c. http://orcid.org/0000-0002-1386-8023;
d. http://orcid.org/0000-0001-7013-4651