1. A clinical guide to periodontology: pathology of periodontal disease;Hasan;Br dent j,2014
2. Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions;Papapanou;J Periodontol,2018
3. A new classification scheme for periodontal and peri-implant diseases and conditions - Introduction and key changes from the 1999 classification;Caton;J Clin Periodontol,2018
4. Development of a classification system for periodontal diseases and conditions;Armitage;Ann Periodontol,1999
5. Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions;Papapanou;J Clin Periodontol,2018