Columbia subject headings:
Harvard subject headings:
America--Economic conditions--Encyclopedias.
America--Encyclopedias.
America--Geography--Encyclopedias.
America--History--Encyclopedias.
America--Maps
America--Politics and government--Encyclopedias.
Central America--History--Encyclopedias.
North America--History--Encyclopedias.
South America--History--Encyclopedias.
Princeton subject headings:
America--Economic conditions--Encyclopedias.
America--Encyclopedias.
America--Geography--Encyclopedias.
America--History--Encyclopedias.
America--Maps.
America--Politics and government--Encyclopedias.
Central America--History--Encyclopedias.
North America--History--Encyclopedias.
South America--History--Encyclopedias.