1. S. Chapman andT. G. Cowling:The Mathematical Theory of Non Uniform Gases, 3rd edition (Cambridge University Press, Cambridge, 1970), sect. 19.6, p. 386.
2. B. Davydov:Phys. Z. Sowjetunion,8, 59 (1935).
3. For the use of d3 V′ instead of d3 V in the first integral, seeW. P. Allis: inHandbuch der Physik, edited byS. Flügge, Vol. 21 (Springer, Berlin, 1956), Chapt. III, sect. 28, p. 404. For the nomenclature seeG. Cavalleri andS. L. Paveri-Fontana:Phys. Rev. A,6, 327 (1972).
4. See, for example, the most recent treatises on electron-atom collisions, asA. Gilardini:Low Energy Electron Collisions in Gases (J. Wiley, New York, N.Y., 1972), eq. (2.3.27);L. B. Loeb:Recent Advances in Basic Processes of Gaseous Electronics (Berkeley University, Berkely, Cal., 1973);L. J. H. Huxley andR. W. Crompton:The Diffusion and Drift of Electrons in Gases (Wiley, New York, N.Y., 1974).
5. G. Cavalleri:Phys. Rev.,179, 186 (1969);D. K. Gibson, R. W. Crompton andG. Cavalleri:J. Phys. B,6, 1118 (1973);T. Rhymes, R. W. Crompton andG. Cavalleri:Phys. Rev. A.,12, 776 (1975).