1. Utilization and evaluation of roent-genograms in periodontal disease;Fröhlich;D. Abs.,1956
2. Use of radiographs in periodontics;Selecky;Georgetown D. J.,1953
3. value of the radiograph and clinical photography in periodontal diagnosis;Ball;North-West Den.,1950
4. Comparison between anatomical and radiographic interpretation of marginal parodontal disease;Fröhlich;Parodont.,1958
5. Crests of the interdental alveolar septa;Ritchey;J. Periodont.,1953