The Portland collection : William John Cavendish Scott Bentinck, 5th Duke of Portland : George Augustus Frederick Cavendish Bentinck : Lady Charlotte Denison [née Bentinck] Viscountess Ossington.
Great Britain.Royal Commission on Historical Manuscripts.
Great Britain.National Register of Archives.
[London?] : [Royal Commission on Historical Manuscripts : National Register of Archives],
[1961?]