APA (7th ed.) Citation

Great Britain. Colonial Office, Great Britain. Public Record Office, & Great Britain. War Office. (1970). Original Correspondence. Public Record Office.

Chicago Style (17th ed.) Citation

Great Britain. Colonial Office, Great Britain. Public Record Office, and Great Britain. War Office. Original Correspondence. London: Public Record Office, 1970.

MLA (8th ed.) Citation

Great Britain. Colonial Office, et al. Original Correspondence. Public Record Office, 1970.