Kolycheva, M. T.; Gerus, I. I.; Kukhar, V. P. Journal of Organic Chemistry USSR (English Translation), 1989 , vol. 25, # 11.2 p. 2134 - 2138 Zhurnal Organicheskoi Khimii, 1989 , vol. 25, # 11 p. 2367 - 2372