Columbia subject headings:
Commerce.
Europe--Economic conditions.
International relations.
Neutrality.
United States--Economic conditions.
World War, 1914-1918--Economic aspects.
Harvard subject headings:
Commerce
Europe--Economic conditions.
International relations
Neutrality.
United States--Economic conditions.
World War, 1914-1918--Economic aspects
Princeton subject headings:
Commerce.
Europe--Economic conditions.
International relations.
Neutrality.
United States--Economic conditions.
World War, 1914-1918--Economic aspects.