“?IMPACT OF COPPER VAPOUR CONTAMINATION ON ARGON ARCS?”, Pakistan Journal of Scientific & Industrial Research, vol. 38, no. 9-10, pp. 379–383, Oct. 1995, Accessed: Apr. 25, 2026. [Online]. Available: http://www.v2.pjsir.org/index.php/biological-sciences/article/view/2526