Columbia subject headings:
Libraries--Germany--History--20th century--Congresses.
Libraries--Italy--History--20th century--Congresses.
Harvard subject headings:
Libraries--Germany--History--20th century--Congresses.
Libraries--Italy--History--20th century--Congresses.
Publishers and publishing--Germany--History--20th century--Congresses.
Publishers and publishing--Italy--History--20th century--Congresses.
Princeton subject headings:
Libraries--Germany--History--20th century--Congresses.
Libraries--Italy--History--20th century--Congresses.
Publishers and publishing--Germany--History--20th century--Congresses.
Publishers and publishing--Italy--History--20th century--Congresses.