1. Hoover Institution, Stanford University (Palo Alto, USA), Gann-Duignan Papers
2. Hoover Institution, Stanford University (Palo Alto, USA), Diana Mitchell Papers
3. The National Archives (Kew, England), Dominions Office and Commonwealth Relations Office Papers
4. National Archives and Records Administration II (College Park, USA), Department of State Central Files
5. National Archives of South Africa (Pretoria, South Africa), Archives of the Accredited Diplomatic Representative, Salisbury