1. The philosophy of the tooth positioning appliance;Kesling;Am J Orthod,1945
2. Invisible retainers;Ponitz;Am j Orthod,1971
3. Invisible retainers;McNamara;J Clin Orthod,1985
4. Essix retainers: Fabrication and supervision for permanent retention;Sheridan;J Clin Orthod,1993
5. Active tooth movement with essix based appliances;Rinchuse;J Clin Orthod,1997