1. H. Molisch and L. Goldschmidt, Monatsh. Chem.,22, 679 (1901).
2. R. A. Soboleva, in: New Medicinal Plants of Siberia and Their Preparations for Treatment [in Russian], Novosibirsk, No. 2 (1946), p. 17.
3. C. A. Marsh, Biochem. J.,59, 59 (1955).
4. I. P. Kovalev and V. I. Litvinenko, Khim. Prirodn. Soedin., 233 (1965).