1. Aalst, W. van, Hollander, J. den, Peterse, W.J.A.M. & Wolff, P.M. de (1976). Acta Cryst. B32, 47–58.
2. Boehme, R. (1982). Acta Cryst A38, 318–326.
3. Fan Hai-fu (1975). Acta Phys. Sin.
24, 57–60.
4. Fan Hai-fu, He Luo, Qian Jin-zi & Lui Shi-xiang (1978). Acta Phys. Sin.
27, 554–558.
5. Fan Hai-fu, Qian Jin-zi, Zheng Chao-de, Gu Yuan-xin Ke Heng-ming & Huang Sheng-hua (1990). Acta Cryst A46 (in the press).