1. Huberman, B.A. & Crutchfield, J.P. Phys. Rev. Lett. 43, 1743 (1979).
2. For an introductory article see, for example, Ruelle, D. La Recherche 11, Feb. 1980, p.132; English translation in Math Intelligencer 2, 126 (1980).
3. Ruelle, D. & Takens, F. Comm. Math. Phys. 20, 167 (1971); 23, 343 (1971).
4. Mandelbrot, B.B. Fractals: Form, Chance and Dimension (Freeman, San Francisco, 1977).
5. Froehling, H., Crutchfield, J.P., Farmer, D., Packard, N.H. & Shaw, R. Physica 3D, 605 (1981).