Vasil'eva, V. P.; Khalfina, I. L.; Karpitskaya, L. G.; Merkushev, E. B. Journal of Organic Chemistry USSR (English Translation), 1987 , vol. 23, # 10 p. 1967 - 1969 Zhurnal Organicheskoi Khimii, 1987 , vol. 23, # 10 p. 2225 - 2227