Columbia subject headings:
America--Foreign relations--United States.
Nonfiction.
Pan American Highway System.
Roads--America--History.
United States--Foreign relations--America.
Harvard subject headings:
America--Foreign relations--United States.
Pan American Highway System.
Roads--America--History.
United States--Foreign relations--America.
Princeton subject headings:
America--Foreign relations--United States.
Pan American Highway System.
Roads--America--History.
United States--Foreign relations--America.