1. Anderton D J and Sale E R 1979Powder Metall. 22 14
2. Chirino A M and Sproule R T 1980Am. Ceram. Soc. Bull. 59 604
3. Das B K 1981 inPreparation and characterization of materials (eds) J M Honig and C N R Rao (New York: Academic Press) p. 213
4. Johnson D W Jr. 1981Am. Ceram. Soc. Bull. 60 221
5. Klug H P and Alexander L E 1974 inX-ray diffraction procedure (New York: Wiley) p. 634