1. Utilization of dental services in the United States;Douglass;J Dent Educ,1979
2. Economies of scale and productivity in dental practices;Nash,1979
3. U.S. Bureau of Census projections of the population of the United States: 1977 to 2050,1977
4. Population estimates and projections: projections of the population of the United States by age, sex and race: 1983 to 2080;Spencer,1984