Mavrov,M.V.; Kucherov,V.F. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1973 , vol. 22, p. 1237 - 1240 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1973 , vol. 22, p. 1279 - 1284