Columbia subject headings:
Europe--Social conditions--20th century.
Social change.
World War, 1914-1918--Causes.
World War, 1914-1918--Influence.
World War, 1939-1945--Causes.
World War, 1939-1945--Influence.
Harvard subject headings:
Europe--Social conditions--20th century.
Social change.
World War, 1914-1918--Causes
World War, 1914-1918--Influence
World War, 1939-1945--Causes.
World War, 1939-1945--Influence.
Princeton subject headings:
Europe--Social conditions--20th century.
Social change.
World War, 1914-1918--Causes.
World War, 1914-1918--Influence.
World War, 1939-1945--Causes.
World War, 1939-1945--Influence.