1. B. Mandelbrot, The Fractal Geometry of Nature (Freeman, San Francisco, 1982).
2. L. V. Kantorovich and G. P. Akilov, Functional Analysis (Nauka, Moscow, 1977) [in Russian].
3. N. Wiener and E. Hopf, Über eine Klasse singularer Integralgleichungen (Acad. Wiss., Berlin, 1932), p. 696.
4. I. Ts. Gokhberg and M. G. Krein, Usp. Mat. Nauk 13 (2), 3 (1958).
5. A. D. Rawlins and W. E. Williams, Quart. J. Mech. Appl. Math. 34, 1 (1981).