1. Flora of the USSR [in Russian], Vol. 28 (1963), p. 364.
2. L. M. Utkin and A. P. Serebryakova, Zh. Obsch. Khim.,34, 3496 (1964).
3. É. T. Organesyan, A. L. Shinkarenko, A. V. Simonyan, and V. I. Frolova, Khim. Prirodn. Soedin, 57 (1972).
4. V. W. Delofe and G. H. Herrero, in: Organic Syntheses [Russian translation], Vol. 3, Moscow (1952), p. 297.
5. A. V. Simonyan, A. L. Shinkarenko, and É. T. Oganesyan, Khim.-Farmats. Zh., No. 10, 59 (1971).