Kalev, Krasimir, and Lyubomir Manov. “A PRELIMINARY STUDY OF PHOTON RADIATION ATTENUATION FROM BALLISTIC PROTECTION MATERIALS”. ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference 4 (June 22, 2024): 160–163. Accessed April 6, 2025. https://journals23.rta.lv/index.php/ETR/article/view/8221.