1. Children at the center. Final report of the National Day Care Center Study,1979
2. Population profile of the United States: 1980;US Bureau of the Census,1981
3. Trends in child care arrangements of working mothers;US Bureau of the Census,1982
4. Marital status and living arrangements;US Bureau of the Census,1982
5. Diarrhea in day care centers;Pickering;Pediatr Infect Dis,1982