Khan, S, M A Khan, and A ul- Haq. “VACUUM HEAT TREATMENT OF ENGINEERING MATERIALS; THE TECHNICAL ASPECT”. Biological Sciences - PJSIR 44, no. 4 (August 20, 2001): 248–252. Accessed November 22, 2024. https://v2.pjsir.org/index.php/biological-sciences/article/view/1936.