p466 Harvey, Alfred, 1911, Castles and Walled Towns of England (Methuen and Co) Mackenzie, J.D., 1897, Castles of England (Heinemann) Vol1 p439-40 Arnold, T. (ed), 1879, Henrici Archidiaconi Huntendunensis Historia Anglorum (London) p266 Trollope, E., 1872, Sleaford and Wapentakes of Flaxwell and Aswardhurn in the County of Lincoln (London) p107-21 Journal articles Brown, R, Allen, 1959, 'A List of Castles, 1154–1216' English Historical Review Vol74 [Reprinted in Brown, R. Allen, 1989, Castles, conquest and charters: collected papers (Woodbridge: Boydell Press) p249-280] Antiquarian William Camden, 1607, Britannia Toulmin Smith, Lucy (ed), 1910, The itinerary of John Leland in or about the years 1535–43 (Bell and Sons; London) Vol1 p26-7 and Vol5 p32 Buildings and structures completed in 1139 Castles in Lincolnshire Grade II listed buildings in Lincolnshire Scheduled monuments in Lincolnshire Sleaford