1. G. Kaupp and A. Herrmann, J. Phys. Org. Chem. 10, 675 (1997); G. Kaupp, A. Herrmann and M. Haak, J. Vac. Sci. Technol. B 15, 1521 (1997); G. Kaupp, Lecture at the NFO-4 Jerusalem, 1997, book of abstracts, p. 92: G. Kaupp and A. Herrmann, Ultramicroscopy (1998), in press; G. Kaupp, Supermicroscopy in Supramolecular Chemistry: AFM, SNOM, and SXM, in Comprehensive Supramolecular Chemistry, Vol. 8, 381-423 + 21 color plates, ed. J. E. D. Davies, Elsevier, Oxford,1996; G. Kaupp, Chemie in unserer Zeit 31, 129 (1997).

2. C. K. Meyer, A. K. Kirsch, G. Vereb, D. Arndt-Jovin and T. M. Jovin, Lecture at the NFO-4 Jerusalem, 1997, book of abstracts, p. 39; N. F. van Hulst, M. H. P. Moers and B Bölger, J. Microsc. 171, 95 (1993); A. Jalocha and N. F. van Hulst, Opt. Commun. 119, 17 (1995).

3. S. I. Bozhevolnyi, M. Xiao and O. Keller, Appl. Opt. 33, 876 (1994); H. Bielefeld, I. Hörsch, G. Krausch, M. Lux-Steiner, J. Mlynek and O. Marti, Appl. Phys. A 59, 103 (1994), a paper which was retreated in Ref. 5; P. J. Moyer and M. A. Paesler, SPIE Scanning Probe Microscopy II 1855, 59 (1993).

4. D. Courjon, J.-M. Vigoureux, M. Spajer, K. Sarayeddine and S. Leblanc, Appl. Opt. 29, 3734 (1990); C. Girard and M. Spajer, ibid. 29, 3726 (1990).

5. V. Sandoghdar, S. Wegscheider, G. Krausch and J. Mlynek, J. Appl. Phys. 81, 2499 (1997).

6. M. Spajer, D. Courjon, K. Sarayeddine, A. Jalocha and J.-M. Vigoureux, J. Phys. (Paris) III 1, 1 (1991); F. Zenhausern,M. P. O'Boyle and H. K. Wickramasinghe, Appl. Phys. Lett. 65, 1623 (1994).

7. S. Madsen, Ph.D.-thesis, Microelectronic Centret at the Technical University of Denmark, Lyngby, 1997.