1. D’Arcy Wentworth Thompson. On Growth and Form. Cambridge University Press, Cambridge, 1944.
2. Mandelbrot BB. The Fractal Geometry of Nature. Freeman, San Francisco, 1982.
3. Richardson LF. The problem of contiguity: an appendix of statistics of deadly quarrels. Gen Sys Yearbook 1961;6:139–187.
4. Vicsek T. Fractal Growth Phenomena. World Scientific, Singapore, 1989.
5. Feder J. Fractals. Plenum Press, New York, 1988.