1. Turner, D. W., Baker, C., Baker, A. D., Brundle, C. R.: Molecular photoelectron spectroscopy. London: Interscience 1970.
2. Siegbahn, K., Nordling, C., Johansson, G., Hedman, J., Hedén, P. F., Hamrin, K., Gelius, U., Bergmark, T., Werme, L. O., Manne, R., Baer, Y.: ESCA Applied to free molecules. Amsterdam: North-Holland Publishing Co. 1969.
3. Siegbahn, K.: J. Electron Spectr. 5, 3 (1974).
4. Berthou, H., Jørgensen, C. K.: Analyt. Chem. 47, 482 (1975).
5. Ng, K. T., Hercules, D. M.: J. Electron Spectr. 7, 257 (1975).