1. Massey, H. S. W., and E. H. S. Burhop: Electronic and Ionic Impact Phenomena. Oxford 1952. — This standard reference contains a thorough discussion of the experimental (Sect. VIII, 5.24) as well as the theoretical (Sect. VIII, 6.6) aspects of inner shell ionization by ion impact, as published up to about 1950. Compare also Sect. II.3 and III.3 for a review of the inner shell ionization by electrons.
2. Mott, N. F., and H. S. W. Massey: The Theory of Atomic Collisions, 2nd ed. Oxford 1949.
3. Bethe, H. A., and J. Ashkin in E. Segrè: Experimental Nuclear Physics, Vol. I, p. 166. New York and London 1953.
4. Henneberg, W.: Z. Physik 86, 592 (1933). — This has been the fundamental theoretical paper in the field. It gives a partial justification for the use of the Born approximation and contains an approximate analytical evaluation.