Piskunov, A. V.; Moroz, A. A.; Shvartsberg, M. S Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1990 , vol. 39, # 6 p. 1303 - 1305 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1990 , # 6 p. 1441 - 1443