Columbia subject headings:
Philosophy, Modern--20th century--Congresses.
Wittgenstein, Ludwig, 1889-1951--Congresses.
Harvard subject headings:
Philosophy--Congresses
Wittgenstein, Ludwig, 1889-1951--Congresses.
Princeton subject headings:
Philosophy--Congresses--History.
Wittgenstein, Ludwig, 1889-1951--Congresses.