Boyanov P. Content of vol. 21, 2021, Journal Scientific and Applied Research: Content of vol. 21, 2021, Journal Scientific and Applied Research. JSAR [Internet]. 2023 Mar. 25 [cited 2024 Dec. 22];21(1):3. Available from: https://jsar.ftn.shu.bg/index.php/jsar/article/view/311