Kramarova, E.P.; Negrebetskii, Vad. V.; Shipov, A.G.; Baukov, Yu. I. Russian Journal of General Chemistry, 1994 , vol. 64, # 7.2 p. 1100 - 1101 Zhurnal Obshchei Khimii, 1994 , vol. 64, # 7 p. 1222 - 1223