1. B. COCKAYNE, W. R. MacEWAN and G. T. BROWN,J. Mater. Sci. 15 (1980) 2785.
2. B. COCKAYNE, W. R. MacEWAN, G. T. BROWN and W. H. E. WILGOSS, ibid.16 (1981) 555.
3. W. B. PPEARSON, ?Handbook of Lattice Spacings and Structure of Metals,? Vol 2 (Pergamon Press, Oxford, 1967).
4. J. W. MELLOR, ?A Comprehensive Treatise on Inorganic and Theoretical Chemistry? Vol. VIII, Supplement III, ?Phosphorus? (Longman Group Ltd, London, 1971) p. 339.
5. N. A. SMITH, I. R. HARRIS, B. COCKAYNE and W. R. MacEWAN,J. Cryst. Growth in press.