Lazov, Lyubomir, Edmunds Teirumnieks, Erika Teirumnieka, Pavel Cacivkin, Nikolay Angelov, and Tsanko Karadzhov. “LABORATORY EXERCISE TO DETERMINE CONTRAST IN LASER MARKING OF ARTICLES”. SOCIETY. INTEGRATION. EDUCATION. Proceedings of the International Scientific Conference 1 (May 21, 2019): 331–339. Accessed May 5, 2024. https://journals.ru.lv/index.php/SIE/article/view/3906.