1. N. F. Goncharov, É. P. Stupakova, and N. F. Komissarenko, Khim. Prir. Soedin., 299 (1987).
2. L. Smid, Pharm. Zentralhalle, No. 36, 430–431 (1940).
3. P. Tunman, Arch. Pharm.,289, No. 12, 704–711 (1956).
4. A. V. Sergeev, Dynamics of the Accumulation of Carotene in Silage Crops, Ucheb. Zap. Yakut. Univ., No. 6, 65–84 (1959).
5. E. S. Kudritskaya, The Carotenoids of Fruits and Berries [in Russian], Vyssha Shkola, Kiev (1990).