1. Principles of retention and avoidance of posttreatment relapse;Reitan;Am J Orthod,1969
2. Retention—the stepchild of orthodontia;Hahn;Angle Orthod,1944
3. Retention procedures for stabilising tooth position after treatment with orthodontic braces;Littlewood;Cochrane Database Syst Rev,2016
4. A removable retainer;Hawley;Int J Orthod Oral Surg,1919
5. Invisible retainers;Ponitz;Am J Orthod,1971