1. 3M Unitek SmartClip: Self-ligating appliance system - Excellence has evolved - The intelligent choice www.3MUnitek.com/SmartClip
2. Dental Practice Board Digest of statistics 2002/2003 www.dpb.nhs.uk
3. GAC International In-Ovation R: The self-ligation system of choice. The mini twin, self-ligating bracket for complete control - start to finish www.gacintl.com
4. Self-ligating brackets: where are we now?;Harradine;Journal of Orthodontics,2003
5. Cochrane Handbook for Systematic Reviews of Interventions 4.2.6 [updated September 2006];Higgins,2006