1. Fluorine in United States Water Supplies;van Burkalow;Geographical Review,1946
2. The Evanston Dental Caries Study, III. A Preliminary Study of the Distribution of Fluorine in Communal Water Supplies in the United States;Hill;Journal of Dental Research,1949
3. Throughout this review, the term “ppm” means “parts per million,” i.e., parts of the element fluorine per million parts of water.
4. Information received by telephone from I. N. Hill, D.D.S., Instructor, Walter G. Zoller Memorial Dental Clinic, University of Chicago, Chicago.
5. Effects of a Penicillin Dentifrice on Caries Incidence in School Children;Zander;J.A.D.A.,1950