Columbia subject headings:
Unmarried couples--Legal status, laws, etc.
Unmarried couples--Legal status, laws, etc.--Great Britain.
Harvard subject headings:
Unmarried couples--Legal status, laws, etc.
Unmarried couples--Legal status, laws, etc.--Great Britain.
Princeton subject headings:
Unmarried couples--Legal status, laws, etc.
Unmarried couples--Legal status, laws, etc.--Great Britain.