Nikiforov, Igor, Pavel Maltsev, Vladimir Ivanov, and Inna Barsuk. “Explanation of the Express Method of the Determination of Steel Grade by Spark”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 16, 2015): 157–161. Accessed May 6, 2024. https://journals.ru.lv/index.php/ETR/article/view/225.