Institution: | (1) Department of General Practice and Community Medicine, Faculty of Medicine, University of Oslo, P.O. Box 1130, Blindern, 0317, Oslo, Norway;(2) Department of Phthisiopulmonology, Northern State Medical University, Troitsky Avenue 51, 163000 Archangel, Russia;(3) Division of Infectious Disease Control, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, 0403, Oslo, Norway |