REFERENCES
- Lovegrove , E. J. , Flett , J. S. and Howe , J. A. 1929 . —Road-making Stones. Attrition Tests in the Light of Petrology. London, 1906; and Mem. Geo!. Survey Britain, “Attrition Tests of British Road Stones”
- Knight , B. H. 1935 . —Road Aggregates, their Use and Testing. London
- Haughton , S. H. 1933 . —Mem. Geol. Survey of S.A., “The Geology of the Neighbourhood of Cape Town”
- Knight , B. H. loco cit.