“SEROPREVALENCE AND RISK FACTORS OF BOVINE RESPIRATORY SYNCYTIAL VIRUS IN DAIRY AND BEEF CATTLE HERDS IN REPUBLIC OF BULGARIA”. TRAKIA JOURNAL OF SCIENCES 22, no. 1 (June 3, 2024): 6. Accessed September 15, 2024. https://tjs.trakia-uni.bg/index.php/tjs/article/view/2.