1. Turner’s experiments are summarized in: D. W. Turner, A. D. Baker, C. Baker, and C. R. Brundle, Molecular Photoelectron Spectroscopy, Wiley, London (1970).
2. F. I. Viselov, B. L. Kurbatov, and A. N. Terenin, Dokl. Akad. Nauk SSSR
138, 1329 (1961).
3. K. Siegbahn, C. Nordling, A. Fahlman, R. Dordberg, K. Hamrin, J. Hedman, G. Johansson, T. Bergark, S.-E. Karlsson, I. Lendgren, and B. Lindberg, ESCA-Atomic, Molecular and Solid State Structure Studied by Means of Electron Spectroscopy, Almqvist and Wiksells, Uppsala (1967).
4. K. Siegbahn, C. Nordling, G. Johansson, J. Hedman, P.-F. Hedén, K. Hamrin, U. Gelius, T. Bergmark, L.-O. Werne, R. Manne, and Y. Baur, ESCA Applied to Free Molecules, North-Holland, Amsterdam (1969).
5. U. Gelius, S. Svensson, H. Siegbahn, E. Basilier, Å. Faxälv, and K. Siegbahn, Chem. Phys. Lett.
28, 1(1974).