Columbia subject headings:
Philosophy, Ancient--20th century--Congresses.
Philosophy, German--20th century--Congresses.
Philosophy--Germany--History--20th century--Congresses.
Philosophy--Greece--History--20th century--Congresses.
Harvard subject headings:
Philosophy, Ancient--20th century--Congresses.
Philosophy, German--20th century--Congresses.
Philosophy--Germany--History--20th century--Congresses.
Philosophy--Greece--History--20th century--Congresses.
Princeton subject headings:
Philosophy, Ancient--20th century--Congresses.
Philosophy, German--20th century--Congresses.
Philosophy--Germany--History--20th century--Congresses.
Philosophy--Greece--History--20th century--Congresses.