Kudryavtsev,B.V.; Yarmukhametova,D.Kh.
Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1970 , p. 1491 - 1494
Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1970 , p. 1583 - 1588