1. Schönherr, O. (1909) Electrotechnische Zeitschrift 22, 365.
2. Linde Co. (1955a) Linde universal inert-gas tungsten-arc cutting of aluminum. Welding J., 34, 1097–1098.
3. Gage, R. M. (1959) The principle of the modern arc torch. Welding J., 38, 959–962.
4. Browing, J. A. (1962) Thermal-air cutting process and economics. Welding J., 41, 132–140.
5. Browing, J. A. and Hazard, C. (1963) Quality determinants in plasma cutting process. British Welding J., 462–469.