1. Sellschop, J.P.F.: Diamond Res. (1975) p. 35.
2. De Beers Industrial Diamond Division, S. Africa: Catalogue and Product Chart (1999).
3. Sumitomo Electric Industries Ltd; Japan: Brochure EV-29R3 (1998-1).
4. Lightowlers, E.C.: Science and Technology of Industrial Diamonds. Vol 1, Burls, J. (ed.), Industrial Diamond Information Bureau, London, 1967, p. 27.
5. Harris, J.W.: Ind. Diamond Rev. 28 (1968) 458.