Columbia subject headings:
Gambling--Philosophy--History--20th century--Congresses.
Play (Philosophy)--History--20th century--Congresses.
Harvard subject headings:
Gambling--Philosophy--History--20th century--Congresses.
Play (Philosophy)--History--20th century--Congresses.
Princeton subject headings:
Gambling--Philosophy--History--20th century--Congresses.
Play (Philosophy)--History--20th century--Congresses.