Columbia subject headings:
Denmark--Foreign relations--1912-1947.
World War, 1914-1918--Denmark.
World War, 1914-1918--Diplomatic history.
Harvard subject headings:
Denmark--Foreign relations--1912-1947.
World War, 1914-1918--Denmark.
World War, 1914-1918--Diplomatic history
Princeton subject headings:
Denmark--Foreign relations--1912-1947.
World War, 1914-1918--Denmark.
World War, 1914-1918--Diplomatic history.