Columbia subject headings:
Nicaragua Canal (Nicaragua)
Nicaragua--Foreign relations--United States.
San Juan River (Nicaragua and Costa Rica)
United States--Foreign relations--Nicaragua.
Harvard subject headings:
Costa Rica--Foreign relations--Nicaragua.
Nicaragua Canal (Nicaragua)
Nicaragua--Foreign relations--Costa Rica.
Nicaragua--Foreign relations--United States.
San Juan River (Nicaragua and Costa Rica)
United States--Foreign relations--Nicaragua.
Princeton subject headings: