1. Nature's method of making perfect root canal fillings following pulp removal with a brief consideration of the development of secondary cementum;Grove;Dent Cosmos,1921
2. Some factors in root canal treatment;Blayney;J Am Dent Assoc,1924
3. Anatomy of the root apex in relation to treatment problems;Coolidge;J Am Dent Assoc,1929
4. Microscopic investigation of root apices;Kuttler;J Am Dent Assoc,1955
5. A stereomicroscopic study of 700 root apices of maxillary and mandibular posterior teeth;Green;Oral Surg Oral Med Oral Pathol,1960