Trends in birth rates in the United States since 1870.
| Egile nagusia: | |
|---|---|
| Formatua: | Liburua |
| Hizkuntza: | English |
| Argitaratua: |
Baltimore
Johns Hopkins Press
1958.
|
| Saila: | The Johns Hopkins University studies in historical and political science
ser. 76, no. 1 |
| Gaiak: |