Ilić, M.; Kopitović, I. .; Vulin, A. .; Zvezdin, B. .; Hromiš, S. .; Kolarov, V. .; Kuhajda, D. .; Vukoja, M. . Frequency and Effects of Seasonal Flu Vaccines on Exacerbations of Chronic Obstructive Pulmonary Disease in Serbia. Vojnosanit Pregl 2021, 78 (2). https://doi.org/10.2298/VSP181214049I.