Antonov, Georgi Stefanov, and Dian Nikiforov Nikolov. “Steel X65 Acc. API 5L Behaviour, under the Influence of CO2 and H2”. ANNUAL JOURNAL OF TECHNICAL UNIVERSITY OF VARNA, BULGARIA 8, no. 2 (October 18, 2024): 10–20. Accessed October 2, 2025. https://aj.tu-varna.bg/index.php/ajtuv/article/view/323.