1. Pohl, M., Coal in Crisis Conference. Johanesburg, 1986, p. 6.
2. The potential of exploiting two of the chemical attributes of pulverized fuel ash (PFA) in South Africa;Heinichen,1994
3. Fly Ash Brick Process;Anderson,2001
4. Jonker, A., Maree, D. B. G. and Van der Merwe, M. J., Guidelines for Ceramic Techniques. Unpublished material. Technikon Pretoria Course Notes, Pretoria, 1996.
5. Clay and Ceramic Raw Materials;Worrall,1986