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 Recommenda- tions 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,p408-S
5. A.I. Gorshkov,Weld. Prod., Vol 15 (No. 7), 1968, p 41; trans, from Russian