1. P. M. Zorkii and I. E. Lubnina, Vestn. Mosk. Univ., Ser. 2: Khim. 40 (5), 300 (1999).
2. K. P. Balashev, Soros. Obraz. Zh. 9, 52 (1998).
3. O. V. Sizova, Doctoral Dissertation in Chemistry (St. Petersburg State Univ., 1998).
4. Yu. A. Borisov and I. I. Kritskaya, Izv. Akad. Nauk SSSR, Ser. Khim., No. 3, 576 (1984).
5. O. S. Mills and G. Robonson, Acta Crystallogr. 16, 758 (1963).