1. A cephalometric study of the soft tissue changes during and after orthodontic treatment;Angelle;Trans Eur Orthod Soc,1973
2. Lip posture and its significance in treatment planning;Burstone;Am J Orthod,1967
3. Incisor tooth retraction and subsequent profile change in postadolescent female patients;Hershey;Am J Orthod,1972
4. Effect of lip training in children with short upper lip;Ingervall;Angle Orthod,1982
5. The influence of lip thickness and strain on upper lip response to incisor retraction;Oliver;Am J Orthod,1982