Stoyanov, S. and Filipova, M. 2023. RESEARCH OF THE VARIATIONS OF THE ATMOSPHERIC OZONE AND CHANGE OF THE ULTRAVIOLET SUN RADIATION OVER NORTHEASTERN BULGARIA. JOURNAL SCIENTIFIC AND APPLIED RESEARCH. 2, 1 (Mar. 2023), 90–93. DOI:https://doi.org/10.46687/jsar.v2i1.48.