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2. Finkelnburg, W. and H. Maecker: “Elektrische Bogen und Thermische Plasmen” Handbuch der Physik, ed. S. Flugge, Vol. XXII, p. 254, Berlin: Springer-Verlag, 1956.
3. von Engel: Ionized Gases, 2nd edition, p. 259, Oxford: Clarendon, 1956.
4. Kesaev, I. G.: Cathode Processes in the Mercury Arc (translated from Russian), p. 30, Consultants Bureau, 1964.
5. Dickson, D. J.: Cathode Region of a Vapor Arc, Nature, p. 64, October 1, 1966.