1. M. R. Nurmukhamedova, Sh. Z. Kazimov, N. D. Abdullaev, G. P. Sidyakin, and M. R. Yagudaev, Khim. Prir. Soedin., 201 (1985).
2. M. R. Nurmukhamedova, N. D. Abdullaev, and G. P. Sidyakin, Khim. Prir. Soedin., 299 (1986).
3. G. V. Sagitdinova, K. A. Éshbakova, Z. A. Khushbaktova, V. M. Malikov, and V. Olimov, Khim. Prir. Soedin., 328 (1992).
4. Hong Yen Hsii and Yu Pan Chen, Phytochemistry,10, 2183 (1971).
5. F. Bohlmann and M. Grenz, Chem. Ber.,105, 3123 (1972).