1. Occurrence of gingivitis in suburban Chicago school children;Massler;Journal of Periodontology,1950
2. A five year longitudinal study of the gingival condition of a group of children in England;Parfitt;Journal of Periodontology,1957
3. Die Häufigkeit der Parodontopathien bei Kindern und Jugendlichen im Alter von 3-18 Jahren;Mieler;Parodontologie and Academy Review,1968
4. Prevalence and distribution of gingivitis-periodontitis in children and adolescents. Epidemiological data as a base for risk group selection;Hugoson;Swedish Dental Journal,1981
5. Experimental gingivitis in man;Löe;Journal of Periodontology,1965