Ter-Gabrielyan, E. G.; Gambaryan, N. P.; Knunyants, I. L. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1981 , vol. 30, # 2 p. 301 - 304 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1981 , # 2 p. 383 - 386