Mohammed Salih, Saad A., et al. “Laser Thermal Input Effects on Deep Penetration CO2 Laser Welding of Carbon Steel”. Nahrain University College of Engineering Journal, vol. 15, no. 2, Sept. 2012, pp. 222-33, https://oldjournal.eng.nahrainuniv.edu.iq/index.php/main/article/view/627.