Feshin, V. P.; Dolgushin, G. V.; Voronkov, M. G.; Gaek, M.; Yanoushek, Z. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1990 , vol. 39, # 4.1 p. 684 - 687 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1990 , # 4 p. 773 - 776