1. B.T.Zhuzbaev, V.V.Veselovsky, A.V.Buevich, and A.M.Moiseenkov,Izv.Akad.Nauk. Ser.Khim., 1993, 122 [Bull.Acad.Sci. Div.Chem.Sci., 1993,42, 110].
2. P. de Mayo,Mono- and Sesquiterpenoids. The Higher Terpenoids. Intersci.Publishers, New York-London, 1959; A.D.Kagarlitsky, S.M.Adekenov, and A.N.Kupriyanov,Seskviterpenovye Laktony Rastenii Tsentral'nogo Kazakhstana (Sesquiterpenoid Lactones of Plants of Central Kazakhstan) (in Russ.) Nauka Kaz. SSR, Alma-Ata, 1987.
3. V.V.Veselovskii, B.T.Zhuzbaev, K.M.Turdybekov, S.M.Adekenov, Yu.T.Struchkov, and A.M.Moiseenkov,Izv.Akad.Nauk. Ser.Khim., 1993, 118 [Bull.Acad.Sci. Div.Chem.Sci., 1993,42, 106].
4. V.V. Veselovsky, V.A. Dragan, N.M. Gafurov, S.M. Adekenov, A.D. Kagarlitskii, B.I. Maksimov, O.S. Chizhov, and A.M. Moiseenkov,Izv.Akad.Nauk. SSSR. Ser.Khim., 1988,37, 2433 [Bull.Acad.Sci. USSR. Div.Chem.Sci., 1988, 2185]; V.V.Veselovsky, B.T.Zhuzbayev, S.M.Adekenov, A.S.Shashkov, and A.M.Moiseenkov,Izv.Akad.Nauk. Ser.Khim., 1992, 658 [Bull.Acad.Sci.Div.Chem.Sci. 1992,41, 517].
5. L.Lombardo,Tetrahedron Lett., 1982,23, 4293.