Ionkin, A. S.; Ignat'eva, S. N.; Arbuzov, B. A. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1990 , vol. 39, # 5.2 p. 1052 - 1054 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1990 , # 5 p. 1169 - 1172