1. R. Hegnauer,Chemotaxonomie der Pflanzen, Bd. 1–6, Basel-Stuttgart,4, 551 (1966);5, 506 (1969);6, 882 (1973).
2. G. Z. Howard, T. I. Mabry, and P. H. Raven,Phytochemistry,11, 289 (1972).
3. H. D. Zinsmeister and S. Bartl,Phytochemistry,10, 3129 (1971).
4. Plant Resources of the USSR [in Russian], Nauka, Leningrad (1987), p. 204.
5. N. I. Bogaevskaya and V. A. Bandyukova,Khim. Prir. Soedin., 285 (1990).