Petrov, V. A.; German, L. S.; Belen'kii, G. G. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1989 , vol. 38, # 2.2 p. 339 - 341 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1989 , # 2 p. 391 - 393