1. For leading references of the chemistry and biochemistry of vitamin D see: Norman, A. W. (1979) Vitamin D, The Calcium Homeostatic Steroid Hormone. Academic Press, New York; DeLuca H. F., Paaren H. E., Schnoes H. K. (1979) Top. Curr. Chem.83: 1; Norman A. W., Schaeffer K., Grigoleit H.-G., Herrath, D. v. (eds.) (1988) Vitamin D: Molecular, Cellular and Clinical Endocrinology. W. d. Gruyter, Berlin; Reichl H., Koeffler H. P., Norman A. W. (1989) New Eng. J. of Med.320: 980
2. Wing R. M., Okamura W. H., Rego A., Pirio M. R., Norman A. W. (1975) J Am. Chem. Soc.97: 4980
3. La Mar G. N., Budd D. J. (1974) J. Am. Chem. Soc.96: 7317
4. Berman E., Luz Z., Mazur Y., Sheves M. (1976) J. Org. Chem.42: 3325. Sheves M., Friedman N., Mazur Y. (1976) J. Org. Chem.42: 3579
5. Okamura W. H., Wing R. M. (1980) In: Norman A. W. (ed.) Vitamin D, Molecular Biology and Clinical Nutrition. Dekker, New York, p 59