Zakharkin, L. I.; Guseva, V. V.; Kamernitskii, D. A. Journal of Organic Chemistry USSR (English Translation), 1989 , vol. 25, # 6.1 p. 1056 - 1059 Zhurnal Organicheskoi Khimii, 1989 , vol. 25, # 6 p. 1173 - 1176