1. H. Raether: In Springer Tracts in Modern Physics, Vol. 38 (Springer Verlag, Berlin, Heidelberg, New York 1965), p. 85.
2. J. Geiger: “Elektronen und Festkörper”, Vol. 128, (Sammlung Vieweg, Braunschweig 1968).
3. J. Daniels, C. v. Festeriberg, H. Raether, K. Zeppenfeld: In Springer Tracts in Modern Physics, Vol. 54, (Springer Berlin, Heidelberg, New York 1970) p. 76.
4. H. Raether: “Excitation of Plasmons and Interband Transitions by Electrons”, in Springer Tracts in Modern Physics, Vol. 88, (Springer Berlin, Heidelberg, New York 1980).
5. R. F. Willis: “Vibrational Spectroscopy of Adsorbates”, in Springer Series in Chemical Physics, Vol. 15 (Springer Berlin, Heidelberg, New York 1980) p. 23.