APA (7th ed.) Citation

Great Britain. Prime Minister & Great Britain. Public Record Office. (1972). Operational correspondence and papers. Public Record Office.

Chicago Style (17th ed.) Citation

Great Britain. Prime Minister and Great Britain. Public Record Office. Operational Correspondence and Papers. London: Public Record Office, 1972.

MLA (8th ed.) Citation

Great Britain. Prime Minister and Great Britain. Public Record Office. Operational Correspondence and Papers. Public Record Office, 1972.