1. Is there a scientific basis for six-monthly dental examinations?;Sheiham;Lancet,1977
2. American Academy of Dental Science;Harris;Dent Cosmos,1879
3. Section of Oral and Dental Surgery;American Medical Association;Dent Cosmos,1890
4. How often should the dentist be visited? The mouth and teeth (brochure),1909
5. Screening for common oral diseases;Deep;J Can Dent Assoc,2000