1. J. Hiernaut, R. Beuker, W. Heinz, R. Selfslag, and M. Hoch, High Temp.-High Press. 18:617 (1986).
2. J. Hiernaut, F. Sakuma, and C. Ronchi, High Temp.-High Press. 21:139 (1989).
3. J. L. Gardner, High Temp.-High Press. 12:699 (1980).
4. J. L. Gardner, T. P. Jones, and M. R. Davies, High Temp.-High Press. 13:459 (1981).
5. P. B. Coates, High Temp.-High Press. 20:433 (1988).