Keiko, N. A.; Rulev, A. Yu.; Kalikhman, I. D.; Voronkov, M. G. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1987 , vol. 36, # 8 p. 1668 - 1671 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1987 , # 8 p. 1801 - 1805