Gambaryan, N. P.; Del'tsova, D. P.; Safronova, Z. V.; Kaitmazova, G. S. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1987 , vol. 36, # 9 p. 1873 - 1875 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1987 , # 9 p. 2022 - 2024