Lermontov, S. A.; Popov, A. V.; Sukhozhenko, I. I.; Martynov, I. V. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1989 , vol. 38, # 1.2 p. 204 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1989 , vol. 38, # 1 p. 215