Columbia subject headings:
Narcotics--Periodicals.
Narcotics.
Opium trade--Periodicals.
Opium trade.
Harvard subject headings:
Drug traffic--Periodicals.
Narcotics--Periodicals.
Opium trade--Periodicals.
Princeton subject headings:
Narcotics--Periodicals.
Opium trade--Periodicals.
Opium trade.
Periodicals.