1. F.T. Arecchi and A. Califano, Phys. Lett. 101A: 443–446 (1984).
2. F.T. Arecchi, R. Badii and A. Politi, Phys. Rev. A32: 402–408 (1985).
3. F.T. Arecchi, “Noise-induced trapping at the boundary between two attractors: a source of 1/f spectra in nonlinear dynamics”, preprint (1986).
4. B. Pompe, J. Kruscha and R.W. Leven, Z. Naturforsch. 41a: 801–808 (1986).
5. E.W. Montroll and M.F. Shlesinger, Proc. Natl. Acad. Sci. USA 79: 3380–3383 (1982).