Grishina, I. I.; Andguladze, M. K.; Kaplun, A. P.; Shvets, V. I.
Journal of Organic Chemistry USSR (English Translation), 1982 , vol. 18, p. 481 - 484
Zhurnal Organicheskoi Khimii, 1982 , vol. 18, # 3 p. 550 - 554

Polonik, S. G.; Tolkach, A. M.; Denisenko, V. A.; Uvarova, N. I.
Chemistry of Natural Compounds, 1983 , vol. 19, # 3 p. 310 - 313
Khimiya Prirodnykh Soedinenii, 1983 , # 3 p. 328 - 331