Columbia subject headings:
Music-halls (Variety-theaters, cabarets, etc.)--Congresses.
Theater--Political aspects--Congresses.
Harvard subject headings:
Music-halls (Variety-theaters, cabarets, etc.)--Austria--History--20th century.
Music-halls (Variety-theaters, cabarets, etc.)--Germany--History--20th century.
Theater--Political aspects--Austria--History--20th century.
Theater--Political aspects--Germany--History--20th century.
Princeton subject headings:
Music-halls (Variety-theaters, cabarets, etc.)--Congresses.
Theater--Political aspects--Congresses.