1. Spinoza, B.: Opera Posthuma, Letter to H. Oldenburg, Voorburg, Nov. 20, 1665, freely translated from the Latin edition of Carl Gebhardt. Heidelberg: Winters 1924
2. Thomas, H.: In: Structural transitions and soft modes. Samuelsen, E.J., Andersen, E., Feder, J. (eds.). Oslo: Universitetforlaget 1971
3. Thomas, H.: In: Anharmonic lattices, structural transitions and melting. Riste, T. (ed.). Leiden: Noordhoff 1974
4. Mandelbrot, B.: The fractal geometry of nature. San Fransisco: Freeman 1982
5. See, e.g.: Time dependent effects in disordered materials. Pynn, R., Riste, T. (eds.). New York: Plenum Press (to be published)