1. V. P. Mikhailova, Tanning Plants of the Flora of Kazakhstan and Their Exploitation, [in Russian], Alma-Ata (1968), p. 120.
2. S. Kh. Chevrenidi, Tanning Plants of Central Asia [in Russian], Tashkent (1965), p. 118.
3. T. Istirher and K. H. Lisken, Arch. Pharm., 295/67, 11, 823 (1962).
4. Beilsteins Handbuch der Org. Chem., Vol. 10 (1925), p. 477.
5. L. Jurd, J. Amer. Chem. Soc.,81, No. 17, 4608 (1959).