DOLCHINKOV, Nikolay; NICHEV, Nikolay. GAMMA-BACKGROUND RADIATION CONTROL SYSTEMS AS A FACTOR OF BULGARIA’S NATIONAL SECURITY. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference, Rezekne, Latvia, v. 4, p. 83–88, 2024. DOI: 10.17770/etr2024vol4.8225. Disponível em: https://journals.ru.lv/index.php/ETR/article/view/8225.. Acesso em: 30 jun. 2024.