Lermontov, S. A.; Rakov, I. M.; Martynov, I. V. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1989 , vol. 38, # 2 p. 1978 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1989 , vol. 9, p. 2149 - 2150