Kryshtal', G. V.; Bogdanov, V. S.; Yanovskaya, L. A.; Volkov, Yu. P.; Trusova, E. I. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1981 , vol. 30, # 12 p. 2351 - 2354 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1981 , # 12 p. 2820 - 2823