1. Levinthal, C. A., Keynan, A., and Higa, A., Proc. US Nat. Acad. Sci., 48, 1631 (1962).
2. Gros, F., Naono, S., Woese, C., Willson, C., and Attardi, G., in Informational Macromolecules (edit. by Vogel, H., Bryson, V., and Lampen, J. O.), 387 (Academic Press, 1963).
3. Salser, W., Jarrin, J., and Levinthal, C., J. Mol. Biol., 31, 237 (1968).
4. Yanofsky, C., and Ito, J., J. Mol. Biol., 21, 313 (1966).
5. Matsushiro, A., Sato, K., Ito, J., Kida, S., and Imamoto, F., J. Mol. Biol., 11, 54 (1965).