Sabev, Sabi, Konstantin Chukalov, and Valeri Bakardzhiev. 2024. “DESIGNING A LABORATORY STAND FOR TESTING IMPACT RESISTANCE OF PLASTIC FILMS BY FREE-FALLING DART DROP ACCORDING ASTM D1709”. ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference 3 (June): 268-73. https://doi.org/10.17770/etr2024vol3.8139.