1. T.R. Thomas, ed.: Rough Surfaces (Longman, Harlow 1992)
2. B. Mandelbrot: The Fractal Geometry of Nature (Freeman, San Francisco 1982)
3. H.-O. Peitgen, P.H. Richter: The Beauty of Fractals (Springer, Berlin, Heidelberg 1986)
4. C.K.R. Varma: Phil. Mag. 1, 959 (1967), Fig. 8.1.
5. D. Avnir, ed.: The Fractal Approach to Heterogeneous Chemistry: Surfaces, Colloids, Polymers (Wiley, Chichester 1989,3rd corrected reprinting 1992)