Bal'on, Ya. G.; Shul'man, M. D.; Smirnov, V. A.; Yukhomenko, M. M.; Yukhomenko, M. A. Journal of Organic Chemistry USSR (English Translation), 1990 , vol. 26, # 7.2 p. 1352 - 1356 Zhurnal Organicheskoi Khimii, 1990 , vol. 26, # 7 p. 1566 - 1571