1. Beurskens, P. T., Bosman, W. P., Doesburg, H. M., Van den Hark, Th. E. M., Prick, P. A. J., Noordik, J. H., Beurskens, G., Gould, R. O., and Parthasarathi, V. (1982)Conformation in Biology, Srinivasan, R., and Sarma, R. H., eds. (Adenine Press, New York), pp. 389?406.
2. Funk, R. L., and Vollhardt, K. P. C. (1980)Synthesis, 118.
3. Grant, D. F., and Gabe, E. J. (1978)J. Appl. Crystallogr. 11, 114?120.
4. Houwen-Claassen, A. A. M. (1988) to be published.
5. International Tables for X-ray Crystallography (1974). Vol. IV (Kynoch Press, Birmingham).