APA (7th ed.) Citation

Great Britain. Public Record Office & Great Britain. Foreign Office. (1974). The opium trade, 1910-1941. Scholarly Resources, Inc.

Chicago Style (17th ed.) Citation

Great Britain. Public Record Office and Great Britain. Foreign Office. The Opium Trade, 1910-1941. Wilmington, Del.: Scholarly Resources, Inc, 1974.

MLA (8th ed.) Citation

Great Britain. Public Record Office and Great Britain. Foreign Office. The Opium Trade, 1910-1941. Scholarly Resources, Inc, 1974.