Andonova, Ivona, et al. “LABORATORY COMPARATIVE ANALYSIS OF SEROLOGICAL AND MOLECULAR BIOLOGICAL METHODS FOR DETECTION OF MEASLES VIRUS IN BULGARIA”. PROBLEMS of Infectious and Parasitic Diseases, vol. 48, no. 2, Oct. 2020, pp. 5-11, https://doi.org/10.58395/pipd.v48i2.25.