1. B. Rossi andK. Greisen:Rev. Mod. Phys.,13, 241 (1940); An account of this is found in the book:B. Rossi:High-Energy Particles (New York, 1952), which is hereafter referred.
2. P. K. Aditya:Korpuskularphotographie,4, 513 (1962).
3. P. K. Aditya:Determination of Distortion in Nuclear Emulsions, to be published.
4. G. Molière:Zeits. f. Naturf.,2 a, 133 (1947);3 a, 78 (1948).
5. K. Gottstein, M. G. K. Menon, J. H. Mulvey, C. O’Ceallaigh andO. Rochat:Phil. Mag.,42, 932 (1951).