Rozhkov, I. N.; Igumnov, S. M.; Pletnev, S. I. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1990 , vol. 39, # 1.2 p. 209 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1990 , # 1 p. 226 - 227