Columbia subject headings:
Opium trade.
United Nations Opium Conference, (1953 : New York). Protocol limiting cultivation of the poppy plant and the international and wholesale trade in and use of opium.
Harvard subject headings:
Opium trade
United Nations Opium Conference (1953 : New York). Protocol limiting cultivation of the poppy plant and the international and wholesale trade in and use of opium.
Princeton subject headings: