1. Bases for referral of endodontic cases;Natkin,1976
2. The anatomy of the root canals of the teeth of the permanent dentition: Part 1;Hess,1925
3. The morphology of the prepared root canal;Davis;Oral Surg Oral Med Oral Pathol,1972
4. The myth of standardized root canal instruments;Luks;NY State Dent J,1973
5. Procedural accidents;Torabinejad,1989