Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), , vol. 31, # 10 p. 2096 - 2099
Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, , # 10 p. 2380 - 2383

Voronkov,M.G. et al.
Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1975 , vol. 24, p. 1932 - 1934
Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1975 , vol. 24, p. 2052 - 2054