1. M. D. Mashkovskii, Drugs [in Russian], Meditsina, Moscow (1977), Part 1, p. 289.
2. V. I. Andrianov, Z. Sh. Safina, and B. L. Tarnopol'skii, Rentgen-75. Automatic System of Programs for the Interpretation of Crystal Structures [in Russian], Inst. Khimicheskoi Fiziki, Academy of Sciences of the USSR, Chernogolovka; Byul. Izobr., (1975).
3. A. N. Chekhlov, Kristallografiya,26, No. 3, 596?598 (1981).
4. S. Kashino, M. E. Ikeda, and M. Haisa, Acta Crystallogr.,38B, 1868?1870 (1982).
5. O. M. Peeters, N. M. Blaton, J. J. de Ranter, et al., Cryst. Struct. Commun.,9, 851?857 (1980).