The Complete Peerage of England, Scotland, Ireland, Great Britain, and the United Kingdom. 1887–98 (8 vols); 1910–59 (13 vols). 6 vols. Gloucester: Alan Sutton, 1982.
Lee-Warner, James. 'The Calthorpes of Burnham'. 04/20/2010 (http://books.google.com/books?id=wjcGAAAAQAAJ&dq=%22norfolk%20archaeology%22%209&pg=RA1-PR11#v=onepage&q&f=false)
Oxford Dictionary of National Biography. 01/05/2005 (http://www.oxforddnb.com)