1. Dental Radiology;O'Brien,1972
2. Beane, L. R.: Personal Communication, Aug. 22, 1975.
3. A Study of Root Resorption in Treated Class II, Division 1 Malocclusions;De Shields;Angle Orthod,1954
4. Apical Root Resorption Under Orthodontic Therapy;Phillips;Angle Orthod,1955
5. Maxillary Central Incisor Root Length in Orthodontically Treated and Untreated Patients;Pelts;Angle Orthod,1974