1. John Cannon, 1969, The Fox-North Coalition, Cambridge, Cambridge University Press.
2. John W. Derry, 1990, Politics in the Age of Fox, Pitt and Liverpool, Basingstoke, Macmillan.
3. E. Anthony Smith, 1973, The Duke of Portland’, in Herbert Van Thal (ed.), The Prime Ministers, Vol. I, London, Allen & Unwin.
4. H.M. Stephens (H.M.S), 1885, Article in Oxford Dictionary of National Biography London, Smith Elder & Co.
5. A.S. Turberville, 1939, A History of Welbeck Abbey and its Owners, Vol. II, London, Faber and Faber.