1. C. M. Hunt, Proceedings of the Fourth International Symposium on the Chemistry of Cement, Washington (1960), National Bureau of Standard Monograph, 43, Vol. 1, p. 297.
2. H. G. Midgley, ibid, p. 479.
3. H. Lehmann and H. Dutz, ibid, p. 513.
4. A. Baron, Bull. Soc. Fr. Ceram, 81 (1968) 73.
5. O. Henning and B. Kassner, Epitoanyag 23 (1971) 414.