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2. I. M. Sharapov, Pharmacology and Toxicology [in Russian], 1959, p. 69.
3. N. I. Koretskaya and L. M. Utkin, Zh. Obshch. Khim., No. 4, 1087 (1958).
4. Progress in Research on Alkaloid-Bearing Plants [in Russian], Kh. N. Aripov (ed.), Fan, Tashkent, 1993, p. 225.
5. Kh. N. Khashimov, Thesis, Tashkent, 1978, p. 68.