Columbia subject headings:
Freedom of movement--European Union countries.
Unmarried couples--Legal status, laws, etc.--European Union countries.
Harvard subject headings:
Freedom of movement--European Union countries
Same-sex marriage--Law and legislation--European Union countries.
Unmarried couples--Legal status, laws, etc.--European Union countries.
Princeton subject headings:
Emigration and immigration law--European Union countries.
Unmarried couples--Legal status, laws, etc.--European Union countries.