Shakhadoyatov, Kh. M.; Yangibaev, S.; Yun, L. M.; Kadyrov, Ch. Sh. Chemistry of Natural Compounds, 1982 , vol. 18, # 1 p. 106 - 111 Khimiya Prirodnykh Soedinenii, 1982 , vol. 18, # 1 p. 112 - 118