1. Anderson, P. W. and Itoh, N.: 1975,Nature 256, 25.
2. Drake, F.: 1973,Astronomy, December issue, p. 5.
3. Eigen, M.: 1972, ?The Origin of Biochemical Information,? in Jagdish Mehra (ed.),The Physicist's Conception of Nature, Reidel, Dordrecht, p. 594.
4. Friedel, J.: 1964,Dislocations, Pergamon Press, New York.
5. Pines, D., Shaham, J., and Ruderman, M.: 1972,Nature Phys. Sci. 237, 83.