Boyanov, Petar, and Petar Boyanov. “Content of Vol. 3, 2013: Content of Vol. 3, 2013”. JOURNAL SCIENTIFIC AND APPLIED RESEARCH 3, no. 1 (March 5, 2023): 3–4. Accessed November 7, 2024. https://jsar.ftn.shu.bg/index.php/jsar/article/view/54.