1. Butterworth, B., “The Properties of Clay Building Materials” in “Ceramics, a Symposium”, edit. A. T. Green and Gerald H. Stewart, Stoke-on-Trent (1953).
2. Anon., Prelim. Rep. by Research Sub-committee, Institution of Engineers, Australia, Melbourne Division, p. 18 (1947).
3. McBurney, J. W., A.S.T.M. Preprint 90 (1954).
4. Schurecht, H. G., and Pole, G. R., J. Amer. Ceram. Soc., 12, 596 (1929).
5. Keppeler, G., and Aurich, G., Sprechsaal, 72, 71 (1939).