1. Oral histology, development, structure, and function;Ten Cate,1980
2. Meyer’s normal histology and histogenesis of the human teeth and associated parts;Churchill,1953
3. Evaluation of unerupted teeth: orthodontic viewpoint;Di Salvo;JADA,1971
4. Orthodontics: current principles and techniques;Graber,1985
5. Traumatic injuries of the tooth;Andreasen,1981