Dzhemilev, U. M.; Dokichev, V. A.; Sultanov, S. Z.; Khusnutdinov, R. I.; Tomilov, Yu. V.; et al.
Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1989 , vol. 38, # 8.2 p. 1707 - 1714
Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1989 , # 8 p. 1861 - 1869

Meijere De, A.; Traetteberg, M.
Journal of Molecular Structure, 1987 , vol. 161, p. 97 - 104