Khachatryan, R. A.; Grigoryan, N. Yu.; Indzhikyan, M. G. Russian Journal of General Chemistry, 1994 , vol. 64, # 8.1 p. 1134 - 1138 Zhurnal Obshchei Khimii, 1994 , vol. 64, # 8 p. 1260 - 1265