Arakelyan, A. S.; Dvoryanchikov, A. I.; Gevorkyan, A. A. Journal of Organic Chemistry USSR (English Translation), 1987 , vol. 23, # 11 p. 2047 - 2050 Zhurnal Organicheskoi Khimii, 1986 , vol. 23, # 11 p. 2323 - 2326