Columbia subject headings:
Harvard subject headings:
Demography--History--20th century--Congresses.
Population--History--20th century--Congresses.
Public health--History--20th century--Congresses.
World War, 1914-1918--Psychological aspects--Congresses.
World War, 1914-1918--Social aspects--Congresses.
Princeton subject headings:
World War, 1914-1918--Social aspects.