1. http://www.allaboutgemstones.com/mohs_hardness_scale.html. Reached on May 07, 2008.
2. The anthropology of modern human teeth;Scott,1997
3. STR-genotyping from human medieval tooth and bone samples;Ricaut;Forensic Science International,2005
4. Teeth;Hillson,1986
5. Advances in Dental Anthropology;Kelly,1991