Zhaishibekov, B. S.; Pat-saev, A. K.; Erzhanov, A. K. Journal of Organic Chemistry USSR (English Translation), 1988 , vol. 24, # 11 p. 2219 - 2220 Zhurnal Organicheskoi Khimii, 1988 , vol. 24, # 11 p. 2460 - 2461