1. Statistical study of the primary causes of extractions;Allen;J. D. Res.,1944
2. Permanent tooth mortality;Andrews;D. Progress,1961
3. Dental disease and its relation to the loss of human teeth;Brekhus;JADA,1929
4. Reasons for extractions in general practice;Coxhead;New Zealand D. J.,1960
5. Survey of 3,874 routine full-mouth radiographs. II. A study of impacted teeth;Dachi;Oral Surg., Oral Med. & Oral Path.,1961