Columbia subject headings:
History, Modern--20th century.
Imperialism--History--20th century.
World War, 1914-1918.
Harvard subject headings:
History, Modern--20th century
Imperialism--History--20th century
World War, 1914-1918
Princeton subject headings:
History, Modern--20th century.
Imperialism--History--20th century.
World War, 1914-1918.