1. H. H. Rossi, Radiation Dosimetry, Vol. 1, Chapter 2, Academic Press (1968).
2. L. D. Landau, J. Phys. USSR, 8 (1944).
3. In ?Principles and Methods of Recording Elementary Particles [in Russian], IIL, Moscow (1963), p. 26.
4. D. West, Proc. Phys. Soc., A66 (1953).
5. U. Fano, Phys. Rev.,92 (1953).