1. Anisotropy in the hardness of single crystals;O'Neill;Proceedings of the Royal Society of London,1971
2. Ceramic Hardness;McColm,1990
3. The Hardness of Metals and its Measurement;O'Neill,1934
4. ASTMSTP 889: Microindentation Techniques in Materials Science and Engineering;Lawn,1986
5. The Science of Hardness Testing and its Research Applications;Westbrook,1973