Odinokov, V. N.; Dzhemilev, U. M.; Ishumuratov, G. Yu.; Botsman, L. P.; Ibragimov, A. G.; et al. Chemistry of Natural Compounds, 1991 , vol. 27, # 2 p. 238 - 240 Khimiya Prirodnykh Soedinenii, 1991 , # 2 p. 276 - 279