1. R. Tschesche, G. Grimmer and F. Neuwald, Chem. Ber., 85, 1103 (1952).
2. M. Okada, J. Pharm. Soc. Japan, 73, 1118 (1953).
3. H. Amato, Chem. Abstr., 62, 6341 (1965).
4. J. Arroyo, L. Carreras and C. Gonzalez, Farmacognosia, 22, 125 (1962).
5. I.F. Makarevich, S.G. Kislichenko, D.G. Kolesnikov, L.Y. Topchii and M.A. Angarskaya, Khim. Prir. Soedin., 45 (1971); Chem. Nat. Comp., 7, 40 (1971).