1. Burke, J. J., Lenoe, E. N. and Katz, R. N. (Eds) (1978). Ceramics for High Performance Applications II (Brook-Hill, Chestnut Hill, Mass, USA).
2. Davis, R. F. (1990). This volume
3. Choyke, W. J. (1990). This volume
4. Jepps, N. W and Page, T F. (1983). Prog. Cryst. Growth and Characterisation, 7, 259–307.
5. Jagodzinski, H. (1949). Acta. Crystallog., 2, 201–207.