1. D.G. Howden,Weld. J., Vol 50 (No, 2), 1971, p 112.
2. D.G. Howden,Weld. J.,Res. Suppl., Vol 61 (No. 4), 1982,p 103-S
3. I.D. Harris, “A Review of Porosity Formation and Recommendations on the Avoidance of Porosity in TIG Welding,” Report 387, The Welding Institute, 1987
4. J.W. Bradley and R.B. McCauley,Weld. J., Res. Suppl., Vol 43 (No. 9), 1964,p 408-S
5. A.I. Gorshkov,Weld. Prod., Vol 15 (No. 7), 1968, p 41; trans, from Russian