Martynov, A. V.; Mirskova, A. N.; Voronkov, M. G. Journal of Organic Chemistry USSR (English Translation), 1989 , vol. 25, # 7.2 p. 1326 - 1328 Zhurnal Organicheskoi Khimii, 1989 , vol. 25, # 7 p. 1470 - 1473