Columbia subject headings:
Harvard subject headings:
Library resources--Great Britain--Directories.
Portugal--Information services--Directories.
Portugal--Library resources--Directories.
Spain--Information services--Directories.
Spain--Library resources--Directories.
Princeton subject headings:
Library resources--Great Britain--Directories.
Portugal--Library resources--Directories.
Spain--Library resources--Directories.
Special libraries--Great Britain--Directories.