Lyashenko, G. S.; Filipova, A. Kh.; Borisova, A. I.; Kalikhman, I. D.; Vyasankin, N. S. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1983 , vol. 32, # 9 p. 1946 - 1948 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1983 , # 9 p. 2153 - 2156