1. V. A. Raldugin, V. A. Khan, Zh. V. Dubovenko, and V. A. Pentegova, Khim. Prirodn. Soedin., 299 (1976).
2. V. A. Raldugin, V. A. Khan, Zh. V. Dubovenko, and V. A. Pentegova, Khim. Prirodn. Soedin., 609 (1976).
3. D. F. Zinkel, I. K. Toda, and J. W. Rowe, Phytochem.,10, 1161 (1971).
4. R. McCrindle and E. Nakamura, Can. J. Chem.,52, 2029 (1974).
5. V. A. Raldugin, O. B. Shelepina, I. P. Sekatsis, A. I. Rezvukhin, and V. A. Pentegova, Khim. Prirodn. Soedin., 108 (1976).