3) Axelsson, P & Lindhe, J: The signifi cance of maintenance care in the treatment of periodontal disease, Journal of Clinical Periodontogy, Vol 8, p.281-294, 1981.
4) Okamoto, H., Yoneyama, T., Llndhe, J., Haffajee, A. & Socransky, S.: Methods of evaluating periodontal disease data in epidemiological research. Journal Clinical Periodontology. Vol 15. p.430-439, 1988.
5) 渡辺是久, Guy Heyden: スウェーデンにおける老人歯科, 歯界展望, 68巻3号, p.641-648, 1986.