1. A. C. Kolb, inProceedings of the Fourth International Conference on Ionization Phenomena in Gases(North-Holland Publishing Company, Amsterdam, 1960), Vol. IV C, p. 1021.
2. R. W. Ziemer, inDynamics of Conducting Gases(North-western University Press, Evanston, 1960), p. 139.
3. V. H. Blackman and B. Niblett, inThe Plasma in a Magnetic Field(Stanford University Press, Stanford, California, 1958), p. 87.