Columbia subject headings:
Family demography--Europe.
Marital status--Europe.
Unmarried couples--Europe--Statistics.
Harvard subject headings:
Family demography--Europe.
Marital status--Europe.
Married people--Europe--Statistics.
Unmarried couples--Europe--Statistics.
Princeton subject headings:
Family demography--Europe.
Marital status--Europe.
Unmarried couples--Europe--Statistics.