Columbia subject headings:
Economics--Dictionaries.
Geography--Dictionaries.
History--Dictionaries.
Political science--Dictionaries.
United Nations.
Harvard subject headings:
Economics--Dictionaries
Economics--Encyclopedias
Geography--Dictionaries
Geography--Encyclopedias
History--Dictionaries
History--Encyclopedias
Political science--Dictionaries
United Nations
Princeton subject headings:
Dictionaries.
Economics--Dictionaries.
Geography--Dictionaries.
History--Dictionaries.
Political science--Dictionaries.
United Nations.