Columbia subject headings:
New Zealand--Commerce--Singapore.
Singapore--Commerce--New Zealand.
Singapore--Commerce--United States.
Tariff preferences--New Zealand.
Tariff preferences--United States.
United States--Commerce--Singapore.
Harvard subject headings:
Singapore--Commerce--United States.
Singapore--Commerce.
Tariff preferences--Singapore.
United States--Commerce--Singapore.
Princeton subject headings:
Singapore--Commerce--United States.
Singapore--Commerce.
Tarif preferences--Singapore.
United States--Commerce--Singapore.