1. J. N. H. Brunt, G. C. King and F.H. Read, A study of resonance structure in helium using metastable excitation by electron impact with high energy resolution, J. Phys. B 10: 433–48 (1977).
2. H. Kuppermann, W. M. Flicker and D. A. Mosher, Electronic spectroscopy of polyatomic molecules by low-energy, variable-angle electron impact, Chem. Reviews 79: 77–90 (1979).
3. R. E. Ballard, J. Jones, D. Read, A. Inshley and M. Cranmer, Auger and electron energy loss studies on liquid surfaces, Chem. Phys. Lett, 147: 629–31 (1988).
4. F. Eschen, M. Heyerhoff, H. Morgner and M. Wulf, unpublished results (1993) M. Heyerhoff, Diplom Thesis, University Bochum, (1993).
5. W. Mehlhorn in Atomic Inner-Shell Physics, ed. B. Craseman, Plenum, New York (1985).