1. The anatomy of the root canals of the teeth of the permanent dentition;Hess,1925
2. Root canal morphology of the human mandibular first molar;Skidmore;Oral Surg,1971
3. Anatomy of root canals. Permanent mandibular molars;Barker;Aust Dent J,1974
4. root canal anatomy of the mandibular first molar;Vertucci;J NJ Dent Assoc,1974
5. root canal anatomy of the mandibular first molar;Vertucci;J NJ Dent Assoc,1974