Columbia subject headings:
Fertility, Human--Korea (South)
Fertility, Human--United States.
Social classes--Korea (South)
Social classes--United States.
Harvard subject headings:
Fertility, Human--Korea (South)
Fertility, Human--United States
Social classes--Korea (South)
Social classes--United States
Princeton subject headings:
Fertility, Human--Korea (South).
Fertility, Human--United States.
Social classes--Korea (South)
Social classes--United States.