1. Sundaralingam, M., The Jerusalem Symposium on Quantum Chemistry and Biochemistry, 5 (edited by Bergmann, E. D., and Pullman, B.) (The Israel Academy of Sciences and Humanities, Jerusalem, 1972).
2. Berthod, H., and Pullman, B., FEES Lett., 30, 231 (1973).
3. Konnert, J., Karle, I. L., and Karle, J., Ada Cryst., B 26, 770 (1970).
4. Saenger, W., and Suck, D., Nature, 242, 610 (1973).
5. Chandrasekhar, K., McPherson, A., Adams, M. J., and Rossmann, M. G., J. molec. Biol, 76, 503 (1973).