1. The development of permanent teeth;Nolla;J Dent Child,1960
2. The timing of orthodontic treatment in relation to tooth formation;Moorrees;Trans Eur Orthod Soc,1962
3. Age variation of formation stages for ten permanent teeth;Moorrees;J Dent Res,1963
4. Stages in the emergence of the dentition;Koyoumdjisky-Kaye;Growth,1977
5. The orthodontic treatment of impacted teeth;Becker,1998