“THE CONTRIBUTION OF THE MILITARY SCHOOL TO THE BUILDING OF THE NATIONAL SECURITY SYSTEM OF BULGARIA IN THE PERIOD 1878-1885”. ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference 4 (June 22, 2024): 155–159. Accessed March 11, 2026. https://archive-journals.rtu.lv/etr/article/view/5083.