1. ?Nitrogen Ceramics?, edited by F. L. Riley, (Noordhoff, Leyden, 1977) In press.
2. A. Atkinson, A. J. Moulson and E. W. Roberts, J. Amer. Ceram. Soc. 59 (1976) 285.
3. A. Atkinson and A. J. Moulson, ?Science of Ceramics?, Vol. 8 (British Ceramic Society, Stokeon-Trent, 1976) p. 111.
4. P. Popper and S. N. Ruddlesden, Tram. Brit. Ceram. Soc. 60 (1961) 603.
5. D. R. Messier and P. Wong, J. Amer. Ceram. Soc. 56 (1973) 480.