Fractals in physics : essays in honour of Benoit B. Mandelbrot : proceedings of the international conference honouring Benoit B. Mandelbrot on his 65th birthday, Vence, France, 1-4 October, 1989 - Aharony, Amnon; Feder, Jens; Mandelbrot, Benoît B. (North-Holland, 1990)